TY  - JOUR
A1  - Xu, Wenlei
A1  - Xu, Yaolin
A1  - Schultz, Thorsten
A1  - Lu, Yan
A1  - Koch, Norbert
A1  - Pinna, Nicola
T1  - Heterostructured and mesoporous Nb2O5@TiO2 core-shell spheres as the negative electrode in Li-ion batteries
JF  - ACS applied materials & interfaces
N2  - Niobium pentoxides have received considerable attention and are promising anode materials for lithium-ion batteries (LIBs), due to their fast Li storage kinetics and high capacity. However, their cycling stability and rate performance are still limited owing to their intrinsic insulating properties and structural degradation during charging and discharging. Herein, a series of mesoporous Nb2O5@TiO2 core-shell spherical heterostructures have been prepared for the first time by a sol-gel method and investigated as anode materials in LIBs. Mesoporosity can provide numerous open and short pathways for Li+ diffusion; meanwhile, heterostructures can simultaneously enhance the electronic conductivity and thus improve the rate capability. The TiO2 coating layer shows robust crystalline skeletons during repeated lithium insertion and extraction processes, retaining high structural integrity and, thereby, enhancing cycling stability. The electrochemical behavior is strongly dependent on the thickness of the TiO2 layer. After optimization, a mesoporous Nb2O5@TiO2 core-shell structure with a similar to 13 nm thick TiO2 layer delivers a high specific capacity of 136 mA h g-1 at 5 A g-1 and exceptional cycling stability (88.3% retention over 1000 cycles at 0.5 A g-1). This work provides a facile strategy to obtain mesoporous Nb2O5@TiO2 core-shell spherical structures and underlines the importance of structural engineering for improving the performance of battery materials.
KW  - mesoporous
KW  - heterostructures
KW  - core-shell spheres
KW  - lithium-ion batteries
Y1  - 2022
U6  - https://doi.org/10.1021/acsami.2c15124
SN  - 1944-8244
SN  - 1944-8252
VL  - 15
IS  - 1
SP  - 795
EP  - 805
PB  - American Chemical Society
CY  - Washington, DC
ER  - 
TY  - JOUR
A1  - Eickenscheidt, Alice
A1  - Lavaux, Valentine
A1  - Paschke, Stefan
A1  - Martinez Guajardo, Alejandro
A1  - Schönemann, Eric
A1  - Laschewsky, Andre
A1  - Lienkamp, Karen
A1  - Staszewski, Ori
T1  - Effect of poly(oxanorbonene)- and poly(methacrylate)-based polyzwitterionic surface coatings on cell adhesion and gene expression of human keratinocytes
JF  - Macromolecular bioscience
N2  - Polyzwitterions are generally known for their anti-adhesive properties, including resistance to protein and cell adhesion, and overall high bio-inertness. 
Yet there are a few polyzwitterions to which mammalian cells do adhere. 
To understand the structural features of this behavior, a panel of polyzwitterions with different functional groups and overall degrees of hydrophobicity is analyzed here, and their physical and biological properties are correlated to these structural differences. Cell adhesion is focused on, which is the basic requirement for cell viability, proliferation, and growth. 
With the here presented polyzwitterion panel, three different types of cell-surface interactions are observed: adhesion, slight attachment, and cell repellency. Using immunofluorescence methods, it is found that human keratinocytes (HaCaT) form focal adhesions on the cell-adhesive polyzwitterions, but not on the sample that has only slight cell attachment. 
Gene expression analysis indicates that HaCaT cells cultivated in the presence of a non-adhesive polyzwitterion have up-regulated inflammatory and apoptosis-related cell signaling pathways, while the gene expression of HaCaT cells grown on a cell-adhesive polyzwitterion does not differ from the gene expression of the growth control, and thus can be defined as fully cell-compatible.
KW  - cell compatibility
KW  - focal adhesion
KW  - gene expression
KW  - immune response
KW  - polyzwitterions
Y1  - 2022
U6  - https://doi.org/10.1002/mabi.202200225
SN  - 1616-5187
SN  - 1616-5195
VL  - 22
IS  - 11
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Feng, Yiqing
A1  - Kochovski, Zdravko
A1  - Arenz, Christoph
A1  - Lu, Yan
A1  - Kneipp, Janina
T1  - Structure and interaction of ceramide-containing liposomes with gold nanoparticles as characterized by SERS and Cryo-EM
JF  - The journal of physical chemistry : C, Nanomaterials and interfaces
N2  - Due to the great potential of surface-enhanced Raman scattering (SERS) as local vibrational probe of lipid-nanostructure interaction in lipid bilayers, it is important to characterize these interactions in detail. 
The interpretation of SERS data of lipids in living cells requires an understanding of how the molecules interact with gold nanostructures and how intermolecular interactions influence the proximity and contact between lipids and nanoparticles. 
Ceramide, a sphingolipid that acts as important structural component and regulator of biological function, therefore of interest to probing, lacks a phosphocholine head group that is common to many lipids used in liposome models. 
SERS spectra of liposomes of a mixture of ceramide, phosphatidic acid, and phosphatidylcholine, as well as of pure ceramide and of the phospholipid mixture are reported. 
Distinct groups of SERS spectra represent varied contributions of the choline, sphingosine, and phosphate head groups and the structures of the acyl chains. Spectral bands related to the state of order of the membrane and moreover to the amide function of the sphingosine head groups indicate that the gold nanoparticles interact with molecules involved in different intermolecular relations. 
While cryogenic electron microscopy shows the formation of bilayer liposomes in all preparations, pure ceramide was found to also form supramolecular, concentric stacked and densely packed lamellar, nonliposomal structures. That the formation of such supramolecular assemblies supports the intermolecular interactions of ceramide is indicated by the SERS data. 
The unique spectral features that are assigned to the ceramide-containing lipid model systems here enable an identification of these molecules in biological systems and allow us to obtain information on their structure and interaction by SERS.
Y1  - 2022
U6  - https://doi.org/10.1021/acs.jpcc.2c01930
SN  - 1932-7447
SN  - 1932-7455
VL  - 126
IS  - 31
SP  - 13237
EP  - 13246
PB  - American Chemical Society
CY  - Washington, DC
ER  - 
TY  - JOUR
A1  - Tritschler, Ulrich
A1  - Delgado López, José Manuel
A1  - Umbach, Tobias R.
A1  - Van Driessche, Alexander E. S.
A1  - Schlaad, Helmut
A1  - Cölfen, Helmut
A1  - Kellermeier, Matthias
T1  - Oriented attachment and aggregation as a viable pathway to self-assembled organic/inorganic hybrid materials
JF  - CrystEngComm
N2  - Organic-inorganic composite materials with tailored properties can be designed in the lab through bioinspired approaches. 
In this context, we exploited the particle-based crystallisation process of calcium sulfate, a technologically important mineral, to hybridise inorganic and organic matter. 
We identified and synthesised an organic polymer showing strong affinity to bind to the surfaces of mineral precursors as well as intrinsic tendency to self-organise. Subsequently, polymer-coated building units were allowed to self-assemble via oriented attachment, aggregation and phase transformation, which produced ordered superstructures where the organic polymer is intercalated between the subunits and surrounds the hybrid core as a shell. 
This specific architecture across multiple length scales leads to unique mechanical properties, comparable to those of natural biominerals. 
Thus, our results devise a straightforward pathway to prepare organic-inorganic hybrid structures via bottom-up self-assembly processes innate to the crystallisation of the inorganic phase. 
This approach can likely be transferred to other inorganic minerals, affording next-generation materials for applications in the construction sector, biomedicine and beyond.
Y1  - 2022
U6  - https://doi.org/10.1039/d2ce00447j
SN  - 1466-8033
VL  - 24
IS  - 36
SP  - 6320
EP  - 6329
PB  - Royal Society of Chemistry
CY  - London
ER  - 
TY  - JOUR
A1  - Cortez, Nicole
A1  - Marin, Victor
A1  - Jimenez, Veronica A.
A1  - Silva, Victor
A1  - Leyton, Oscar
A1  - Cabrera-Pardo, Jaime R.
A1  - Schmidt, Bernd
A1  - Heydenreich, Matthias
A1  - Burgos, Viviana
A1  - Duran, Paola
A1  - Paz, Cristian
T1  - Drimane sesquiterpene alcohols with activity against Candida yeast obtained by biotransformation with Cladosporium antarcticum
JF  - International journal of molecular sciences
N2  - Fungal biotransformation is an attractive synthetic strategy to produce highly specific compounds with chemical functionality in regions of the carbon skeleton that are not easily activated by conventional organic chemistry methods. 
In this work, Cladosporium antarcticum isolated from sediments of Glacier Collins in Antarctica was used to obtain novel drimane sesquiterpenoids alcohols with activity against Candida yeast from drimendiol and epidrimendiol. These compounds were produced by the high-yield reduction of polygodial and isotadeonal with NaBH4 in methanol. 
Cladosporium antarcticum produced two major products from drimendiol, identified as 9 alpha-hydroxydrimendiol (1, 41.4 mg, 19.4% yield) and 3 beta-hydroxydrimendiol (2, 74.8 mg, 35% yield), whereas the biotransformation of epidrimendiol yielded only one product, 9 beta-hydroxyepidrimendiol (3, 86.6 mg, 41.6% yield). 
The products were purified by column chromatography and their structure elucidated by NMR and MS. The antifungal activity of compounds 1-3 was analyzed against Candida albicans, C. krusei and C. parapsilosis, showing that compound 2 has a MIC lower than 15 mu g/mL against the three-pathogenic yeast. 
In silico studies suggest that a possible mechanism of action for the novel compounds is the inhibition of the enzyme lanosterol 14 alpha-demethylase, affecting the ergosterol synthesis.
KW  - Drimys winteri
KW  - Cladosporium antarcticum
KW  - drimendiol
KW  - epidrimendiol
KW  - biotransformation
KW  - Candida yeast
KW  - lanosterol 14 alpha-demethylase
KW  - biocontrol
Y1  - 2022
U6  - https://doi.org/10.3390/ijms232112995
SN  - 1422-0067
VL  - 23
IS  - 21
PB  - MDPI
CY  - Basel
ER  - 
TY  - JOUR
A1  - Marin, Victor
A1  - Bart, Bryan
A1  - Cortez, Nicole
A1  - Jiménez, Verónica A.
A1  - Silva, Victor
A1  - Leyton, Oscar
A1  - Cabrera-Pardo, Jaime R.
A1  - Schmidt, Bernd
A1  - Heydenreich, Matthias
A1  - Burgos, Viviana
A1  - Paz, Cristian
T1  - Drimane sesquiterpene aldehydes control Candida yeast isolated from candidemia in Chilean patients
JF  - International journal of molecular sciences
N2  - Drimys winteri J.R. (Winteraceae) produce drimane sesquiterpenoids with activity against Candida yeast. 
In this work, drimenol, polygodial (1), isotadeonal (2), and a new drimane alpha,beta-unsaturated 1,4-dialdehyde, named winterdial (4), were purified from barks of D. winteri. The oxidation of drimenol produced the monoaldehyde drimenal (3). 
These four aldehyde sesquiterpenoids were evaluated against six Candida species isolated from candidemia patients in Chilean hospitals. 
Results showed that 1 displays fungistatic activity against all yeasts (3.75 to 15.0 mu g/mL), but irritant effects on eyes and skin, whereas its non-pungent epimer 2 has fungistatic and fungicide activities at 1.9 and 15.0 mu g/mL, respectively. 
On the other hand, compounds 3 and 4 were less active. 
Molecular dynamics simulations suggested that compounds 1-4 are capable of binding to the catalytic pocket of lanosterol 14-alpha demethylase with similar binding free energies, thus suggesting a potential mechanism of action through the inhibition of ergosterol synthesis. According to our findings, compound 2 appears as a valuable molecular scaffold to pursue the future development of more potent drugs against candidiasis with fewer side effects than polygodial. 
These outcomes are significant to broaden the alternatives to treat fungal infections with increasing prevalence worldwide using natural compounds as a primary source for active compounds.
KW  - drimane sesquiterpenoids
KW  - Drimys winteri
KW  - isotadeonal
KW  - winterdial
KW  - Candida yeast
KW  - lanosterol 14-α-demethylase
KW  - molecular dynamics
Y1  - 2022
U6  - https://doi.org/10.3390/ijms231911753
SN  - 1422-0067
VL  - 23
IS  - 19
PB  - Molecular Diversity Preservation International
CY  - Basel
ER  - 
TY  - JOUR
A1  - Schürmann, Robin
A1  - Dutta, Anushree
A1  - Ebel, Kenny
A1  - Tapio, Kosti
A1  - Milosavljevic, Aleksander R.
A1  - Bald, Ilko
T1  - Plasmonic reactivity of halogen thiophenols on gold nanoparticles studied by SERS and XPS
JF  - The journal of chemical physics : bridges a gap between journals of physics and journals of chemistr
N2  - Localized surface plasmon resonances on noble metal nanoparticles (NPs) can efficiently drive reactions of adsorbed ligand molecules and provide versatile opportunities in chemical synthesis. The driving forces of these reactions are typically elevated temperatures, hot charge carriers, or enhanced electric fields. 
In the present work, dehalogenation of halogenated thiophenols on the surface of AuNPs has been studied by surface enhanced Raman scattering (SERS) as a function of the photon energy to track the kinetics and identify reaction products. 
Reaction rates are found to be surprisingly similar for different halothiophenols studied here, although the bond dissociation energies of the C-X bonds differ significantly. Complementary information about the electronic properties at the AuNP surface, namely, work-function and valence band states, has been determined by x-ray photoelectron spectroscopy of isolated AuNPs in the gas-phase. 
In this way, it is revealed how the electronic properties are altered by the adsorption of the ligand molecules, and we conclude that the reaction rates are mainly determined by the plasmonic properties of the AuNPs. SERS spectra reveal differences in the reaction product formation for different halogen species, and, on this basis, the possible reaction mechanisms are discussed to approach an understanding of opportunities and limitations in the design of catalytical systems with plasmonic NPs.
Y1  - 2022
U6  - https://doi.org/10.1063/5.0098110
SN  - 0021-9606
SN  - 1089-7690
VL  - 157
IS  - 8
PB  - American Institute of Physics
CY  - Melville, NY
ER  - 
TY  - JOUR
A1  - Braune, S.
A1  - Baeckemo, J.
A1  - Lau, S.
A1  - Heuchel, M.
A1  - Kratz, K.
A1  - Jung, F.
A1  - Reinthaler, M.
A1  - Lendlein, Andreas
T1  - The influence of different rewetting procedures on the thrombogenicity of nanoporous poly(ether imide) microparticles
JF  - Clinical hemorheology and microcirculation : blood flow and vessels
N2  - Nanoporous microparticles prepared from poly(ether imide) (PEI) are discussed as candidate adsorber materials for the removal of uremic toxins during apheresis. Polymers exhibiting such porosity can induce the formation of micro-gas/air pockets when exposed to fluids. Such air presenting material surfaces are reported to induce platelet activation and thrombus formation. Physical or chemical treatments prior to implantation are discussed to reduce the formation of such gas nuclei. Here, we report about the influence of different rewetting procedures - as chemical treatments with solvents on the thrombogenicity of hydrophobic PEI microparticles and PEI microparticles hydrophilized by covalent attachment of poly(vinyl pyrrolidone) (PVP) of two different chain lengths. <br /> Autoclaved dry PEI particles of all types with a diameter range of 200 - 250 mu m and a porosity of about 84%+/- 2% were either rewetted directly with phosphate buffered saline (24 h) or after immersion in an ethanol-series. Thrombogenicity of the particles was studied in vitro upon contact with human sodium citrated whole blood for 60 min at 5 rpm vertical rotation. Numbers of non-adherent platelets were quantified, and adhesion of blood cells was qualitatively analyzed by bright field microscopy. Platelet activation (percentage of CD62P positive platelets and amounts of soluble P-Selectin) and platelet function (PFA100 closure times) were analysed. <br /> Retention of blood platelets on the particles was similar for all particle types and both rewetting procedures. Non-adherent platelets were less activated after contact with ethanol-treated particles of all types compared to those rewetted with phosphate buffered saline as assessed by a reduced number of CD62P-positive platelets and reduced amounts of secreted P-Selectin (P < 0.05 each). Interestingly, the hydrophilic surfaces significantly increased the number of activated platelets compared to hydrophobic PEI regardless of the rewetting agent. This suggests that, apart from wettability, other material properties might be more important to regulate platelet activation. PFA100 closure times were reduced and within the reference ranges in the ethanol group, however, significantly increased in the saline group. No substantial difference was detected between the tested surface modifications. In summary, rewetting with ethanol resulted in a reduced thrombogenicity of all studied microparticles regardless of their wettability, most likely resulting from the evacuation of air from the nanoporous particles.
KW  - biomaterial
KW  - polymer
KW  - microparticle
KW  - thrombogenicity
KW  - hemocompatibility
KW  - dynamic in-vitro test
KW  - rewetting
Y1  - 2021
U6  - https://doi.org/10.3233/CH-201029
SN  - 1386-0291
SN  - 1875-8622
VL  - 77
IS  - 4
SP  - 367
EP  - 380
PB  - IOS Press
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Farrokhzadeh, Abdolkarim
A1  - Modarresi-Alam, Ali Reza
A1  - Akher, Farideh Badichi
A1  - Kleinpeter, Erich
A1  - Kelling, Alexandra
A1  - Schilde, Uwe
T1  - Investigation of the unusually high rotational energy barrier about the C-N bond in 5-(2-x-phenyl)-N,N-dimethyl-2H-tetrazole-2-carboxamides
BT  - insights from dynamic H-1-NMR and DFT calculations
JF  - Journal of molecular structure
N2  - In this study, the synthesis of new 5 (2-x-phenyl)-N,N-dimethyl-2H-tetrazole-2-carboxamides (X = H and Cl) is reported coupled with the investigation of their dynamic H-1-NMR via rotation about C-N bonds in the moiety of urea group [a; CO-NMe2] in DMSO solvent (298-373 K). Accordingly, activation free energies of 17.32 and 17.50 kcal mol(-1) were obtained for X = H and Cl respectively, with respect to the conformational isomerization about the Me2N-C=O bond (a rotation). Moreover, a and b [b; 2-tetrazolyl-CO rotations] barrier to rotations in 5-(2-x-phenyl)-N,N-dimethyl-2H-tetrazole-2-carboxamides were also calculated by B3LYP/6-311++G** procedure. The optimized geometry parameters are well consistent with the X-ray data. Computed rotational energy barriers (X = Cl) for a and b were estimated to be 17.52 and 2.53 kcal mol(-1), respectively, the former in agreement with the dynamic NMR results. X-ray structures verify that just 2-acylated tetrazoles are formed in the case of 5-(2-x-phenyl)-N,N-dimethyl-2H-tetrazole-2-carboxamides. A planar trigonal orientation of the Me2N group was proven by X-ray data, which is coplanar to the carbonyl group, coupled with partial double bond C-N character. This also illustrates the syn-periplanar position of the tetrazolyl ring with C=O group. In solution, the planes containing tetrazolyl ring and the carbonyl bond are almost perpendicular to each other (because of steric effects as confirmed by calculations) while the planes containing carbonyl bond and Me2N group are coplanar. This phenomenon is in contrast with similar urea derivatives and explains the reason for the unusually high rotational energy barrier of these compounds. (C) 2020 Elsevier B.V. All rights reserved.
KW  - carbamoyl tetrazoles
KW  - barrier to rotation about C-N bond
KW  - dynamic
KW  - H-1-NMR
KW  - quantum mechanical calculations
KW  - X-ray structures
Y1  - 2020
U6  - https://doi.org/10.1016/j.molstruc.2020.129363
SN  - 0022-2860
SN  - 1872-8014
VL  - 1226
IS  - Part B
PB  - Elsevier
CY  - New York, NY
ER  - 
TY  - JOUR
A1  - Stojanović, Ivan
A1  - Židov, Bruno
A1  - Travkova, Oksana
A1  - Grigoriev, Dmitry
T1  - Enhanced protective performance of waterborne, microcontainers-doped coatings in harsh environments
JF  - Progress in organic coatings : an international journal
N2  - In this study, the corrosion inhibitors Zinc oleate and 8-Hydroxyquinoline were successfully encapsulated using an interfacial polyaddition method. As such they were dispersed at different concentrations within the waterborne coating matrix. The resulting composite coatings were applied to the low carbon steel substrates. Successful synthesis and morphological characteristics of microcontainers loaded with inhibitors were confirmed using various characterization techniques. Scanning electron microscopy, dynamic light scattering, and thermogravimetric measurements are techniques used to define the surface, dimensional, and dispersive characteristics of containers, and the share of encapsulated inhibitors. The release study defined the discharge kinetics of the corrosion inhibitor from the microcontainers dispersed freely in an aqueous medium. Electrochemical impedance spectroscopy was used to determine the anticorrosive performance of the samples continuously exposed to various corrosive environments of salt and humidity chambers and NaCl solution. Special emphasis was placed on adhesion testing and visual observations during the exposure period. Significant improvements have been noted in terms of corrosion resistance, which, however, depend on the type of inhibitor used, the concentration of the containers embedded in the coating matrix and on the characteristics of the corrosive environment.
KW  - Self-protecting coatings
KW  - Interfacial polyaddition
KW  - Inhibitor loaded
KW  - microcontainers
KW  - Corrosion inhibitors
Y1  - 2021
U6  - https://doi.org/10.1016/j.porgcoat.2021.106273
SN  - 0300-9440
SN  - 1873-331X
VL  - 157
PB  - Elsevier Science
CY  - Amsterdam [u.a.]
ER  - 
TY  - JOUR
A1  - Gahlaut, Shashank K.
A1  - Pathak, Anisha
A1  - Gupta, Banshi D.
T1  - Recent advances in silver nanostructured substrates for plasmonic sensors
JF  - Biosensors : open access journal
N2  - Noble metal nanostructures are known to confine photon energies to their dimensions with resonant oscillations of their conduction electrons, leading to the ultrahigh enhancement of electromagnetic fields in numerous spectroscopic methods. 
Of all the possible plasmonic nanomaterials, silver offers the most intriguing properties, such as best field enhancements and tunable resonances in visible-to-near infrared regions. 
This review highlights the recent developments in silver nanostructured substrates for plasmonic sensing with the main emphasis on surface plasmon resonance (SPR) and surface-enhanced Raman spectroscopy (SERS) over the past decade. 
The main focus is on the synthesis of silver nanostructured substrates via physical vapor deposition and chemical synthesis routes and their applications in each sensing regime. 
A comprehensive review of recent literature on various possible silver nanostructures prepared through these methodologies is discussed and critically reviewed for various planar and optical fiber-based substrates.
KW  - silver
KW  - plasmonics
KW  - sensors
KW  - surface-enhanced Raman spectroscopy
KW  - surface-enhanced fluorescence
KW  - surface-enhanced infrared spectroscopy
Y1  - 2022
U6  - https://doi.org/10.3390/bios12090713
SN  - 2079-6374
VL  - 12
IS  - 9
PB  - MDPI
CY  - Basel
ER  - 
TY  - JOUR
A1  - Diehn, Sabrina Maria
A1  - Schlaad, Helmut
A1  - Kneipp, Janina
T1  - Multivariate imaging for fast evaluation of in situ dark field microscopy hyperspectral data
JF  - Molecules : a journal of synthetic chemistry and natural product chemistry
N2  - Dark field scattering microscopy can create large hyperspectral data sets that contain a wealth of information on the properties and the molecular environment of noble metal nanoparticles. 
For a quick screening of samples of microscopic dimensions that contain many different types of plasmonic nanostructures, we propose a multivariate analysis of data sets of thousands to several hundreds of thousands of scattering spectra. 
By using non-negative matrix factorization for decomposing the spectra, components are identified that represent individual plasmon resonances and relative contributions of these resonances to particular microscopic focal volumes in the mapping data sets. Using data from silver and gold nanoparticles in the presence of different molecules, including gold nanoparticle-protein agglomerates or silver nanoparticles forming aggregates in the presence of acrylamide, plasmonic properties are observed that differ from those of the original nanoparticles. 
For the case of acrylamide, we show that the plasmon resonances of the silver nanoparticles are ideally suited to support surface enhanced Raman scattering (SERS) and the two-photon excited process of surface enhanced hyper Raman scattering (SEHRS). Both vibrational tools give complementary information on the in situ formed polyacrylamide and the molecular composition at the nanoparticle surface.
KW  - localized surface plasmon resonances
KW  - gold nanoparticles
KW  - silver nanoparticles
KW  - dark field microscopy
KW  - acrylamide
KW  - hyperspectral imaging
KW  - non-negative matrix factorization
KW  - surface-enhanced Raman scattering (SERS)
KW  - surface-enhanced hyper Raman scattering (SEHRS)
Y1  - 2022
U6  - https://doi.org/10.3390/molecules27165146
SN  - 1420-3049
VL  - 27
IS  - 16
PB  - MDPI
CY  - Basel
ER  - 
TY  - JOUR
A1  - Tarazona, Natalia A.
A1  - Wei, Ren
A1  - Brott, Stefan
A1  - Pfaff, Lara
A1  - Bornscheuer, Uwe T.
A1  - Lendlein, Andreas
A1  - Machatschek, Rainhard
T1  - Rapid depolymerization of poly(ethylene terephthalate) thin films by a dual-enzyme system and its impact on material properties
JF  - Chem Catalysis
N2  - Enzymatic hydrolysis holds great promise for plastic waste recycling and upcycling. 
The interfacial catalysis mode, and the variability of polymer specimen properties under different degradation conditions, add to the complexity and difficulty of understanding polymer cleavage and engineering better biocatalysts. 
We present a systemic approach to studying the enzyme-catalyzed surface erosion of poly(ethylene terephthalate) (PET) while monitoring/controlling operating conditions in real time with simultaneous detection of mass loss and changes in viscoelastic behavior. 
PET nanofilms placed on water showed a porous morphology and a thicknessdependent glass transition temperature (T-g) between 40 degrees C and 44 degrees C, which is >20 degrees C lower than the T-g of bulk amorphous PET. 
Hydrolysis by a dual-enzyme system containing thermostabilized variants of Ideonella sakaiensis PETase and MHETase resulted in a maximum depolymerization of 70% in 1 h at 50 degrees C. 
We demonstrate that increased accessible surface area, amorphization, and T-g reduction speed up PET degradation while simultaneously lowering the threshold for degradation-induced crystallization.
Y1  - 2022
U6  - https://doi.org/10.1016/j.checat.2022.11.004
SN  - 2667-1093
SN  - 2667-1107
VL  - 2
IS  - 12
SP  - 3573
EP  - 3589
PB  - Cell Press
CY  - Cambridge
ER  - 
TY  - JOUR
A1  - Rothe, Martin
A1  - Zhao, Yuhang
A1  - Halim, Henry
A1  - Lu, Yan
A1  - Benson, Oliver
T1  - Spatial mapping of bleaching in a metal-organic plasmon converter
JF  - Optics continuum
N2  - Hybrid nanophotonic elements, fabricated by organic and inorganic materials, are going to be key components of modern devices. 
Coupled systems of photoemitters with a plasmonic waveguide serve the demand for nanoscopic frequency converters. 
However, processes like the degradation of the photoemitters via photobleaching occur and need to be monitored and controlled, to realize future successful devices. 

We introduce a hybrid perylene-diimide / silver nanowire as plasmon frequency converter. A versatile method is presented to monitor and analyze the bleaching process. It is based on a time series of photoluminescence images, during the operation of a single converter. 
An analytical model is applied on the data and unveils that the photobleaching rate is constant and independent of the operation of the plasmon converter.
Y1  - 2022
U6  - https://doi.org/10.1364/OPTCON.454911
SN  - 2770-0208
VL  - 1
IS  - 8
SP  - 1730
EP  - 1740
PB  - Optica Publishing Group
CY  - Washington
ER  - 
TY  - JOUR
A1  - Chemura, Sitshengisiwe
A1  - Schrumpf, Tim
A1  - Günter, Christina
A1  - Kumke, Michael Uwe
T1  - Ceria nanomaterials containing Ytterbium
BT  - Low and high concentration – luminescence analyzed in the near infrared region
JF  - RSC Advances : an international journal to further the chemical sciences
N2  - Lanthanide based ceria nanomaterials are important practical materials due to the redox properties that are useful in the avenues pertaining to technology and life sciences. Sub 10 nm spherical and highly monodisperse Ce1−xYbxO2−y (0.04 ≤ x ≤ 0.22) nanoparticles were synthesized by thermal decomposition, annealed separately at 773 K and 1273 K for 2 hours and characterized. Elemental mapping for Yb3+ doped ceria nanoparticles shows homogeneous distribution of Yb3+ atoms in the ceria with low Yb3+ content annealed at 773 K and 1273 K for 2 hours. However, clusters are observed for 773 K annealed ceria samples with high concentration of Yb3+. These clusters are not detected in 1273 K annealed nanomaterials. Introducing small amounts of Yb3+ ions into the ceria lattice as spectroscopic probes can provide detailed information about the atomic structure and local environments allowing the monitoring of small structural changes, such as clustering. The emission spectra observed at room temperature and at 4 K have a manifold of bands that corresponds to the 2F5/2 → 2F7/2 transition of Yb3+ ions. Some small shifts are observed in the Stark splitting pattern depending on the sample and the annealing conditions. The deconvolution by PARAFAC analysis yielded luminescence decay kinetics as well as the associated luminescence spectra of three species for each of the low Yb3+ doped ceria samples annealed at 773 K and one species for the 1273 K annealed samples. However, the ceria samples with high concentration of Yb3+ annealed at the two temperatures showed only one species with lower decay times as compared to the low Yb3+ doped ceria samples.
Y1  - 2023
U6  - https://doi.org/10.1039/D3RA06868D
SN  - 2046-2069
VL  - 13
IS  - 50
SP  - 35445
EP  - 35456
PB  - RSC Publishing
CY  - London
ER  - 
TY  - JOUR
A1  - Lehnen, Anne-Catherine
A1  - Kurki, Jan A. M.
A1  - Hartlieb, Matthias
T1  - The difference between photo-iniferter and conventional RAFT polymerization
BT  - high livingness enables the straightforward synthesis of multiblock copolymers
JF  - Polymer Chemistry
N2  - Photo-iniferter (PI)-RAFT polymerization, the direct activation of chain transfer agents via light, is a fascinating polymerization technique, as it overcomes some restriction of conventional RAFT polymerization. 
As such, we elucidated the role of reversible deactivation in this context using a monomer-CTA pair with low chain transfer capabilities. 
Tests with varying targeted degrees of polymerization (DP) or monomer concentrations revealed no significant improvement of polymerization control using the PI-process. Control can however be achieved via slow monomer addition, increasing the number of activation/deactivation events per monomer addition. 
More importantly, the livingness of the polymerization was found to be extraordinarily high, enabling the straightforward and rapid synthesis of multiblock copolymers with up to 20 blocks and a high number of repeating units per block (DP = 25-100) maintaining an overall excellent definition (M-n = 90 300 g mol(-1), D = 1.29). 
This study highlights the enormous potential of PI-RAFT polymerization for the synthesis of polymeric materials.
Y1  - 2022
U6  - https://doi.org/10.1039/d1py01530c
SN  - 1759-9954
SN  - 1759-9962
VL  - 13
IS  - 11
SP  - 1537
EP  - 1546
PB  - Royal Society of Chemistry
CY  - Cambridge
ER  - 
TY  - JOUR
A1  - Hermanns, Jolanda
A1  - Kunold, Helen
T1  - Mechanism comics as a task in a written exam in organic chemistry for pre-service chemistry teachers
JF  - Chemistry teacher international : best practices in chemistry education
N2  - In this paper, we describe and evaluate a study on the use of mechanism comics for writing solutions to a task in a written exam for the course "Organic Chemistry I for Pre-Service Chemistry Teachers." 
The students had to design a reaction mechanism for a reaction that was unknown to them and write captions explaining every step of their reaction mechanism. 
The students' work was evaluated using the method of qualitative content analysis in four rounds by both authors. The majority of the captions were coded as "descriptive" and only a minority as "causal." 
This means that the students mostly described "what" happened, but seldom "why" this happened. Implicit electron movement was also described more often than explicit electron movement. The majority of the captions were technically correct. In summary, the students were capable of designing and describing a reaction mechanism for a previously unknown reaction. 
The quality of their reasoning could be improved, however. In the new course, the quality of students' mechanistic reasoning and then especially their explanations of "why" mechanistic steps occur will be given much clearer emphasis.
KW  - concepts
KW  - mechanistic reasoning
KW  - organic chemistry
KW  - pre-service chemistry teachers
KW  - writing-to-learn
Y1  - 2022
U6  - https://doi.org/10.1515/cti-2021-0035
SN  - 2569-3263
VL  - 4
IS  - 3
SP  - 259
EP  - 269
PB  - De Gruyter
CY  - Berlin
ER  - 
TY  - JOUR
A1  - Titov, Evgenii
T1  - Effect of conformational disorder on exciton states of an azobenzene aggregate
JF  - Physical chemistry, chemical physics : a journal of European Chemical Societies
N2  - Azobenzene is a prototypical molecular photoswitch, widely used to trigger a variety of transformations at different length scales. 
In systems like self-assembled monolayers or micelles, azobenzene chromophores may interact with each other, which gives rise to the emergence of exciton states. 

Here, using first-principles calculations, we investigate how conformational disorder (induced, e.g., by thermal fluctuations) affects localization of these states, on an example of an H-type azobenzene tetramer. 

We find that conformational disorder leads to (partial) exciton localization on a single-geometry level, whereas ensemble-averaging results in a delocalized picture. The pi pi* and n pi* excitons at high and low temperatures are discussed.
Y1  - 2022
U6  - https://doi.org/10.1039/d2cp02774g
SN  - 1463-9076
SN  - 1463-9084
VL  - 24
IS  - 39
SP  - 24002
EP  - 24006
PB  - Royal Society of Chemistry
CY  - Cambridge
ER  - 
TY  - JOUR
A1  - Sand, Patrick
A1  - Schmidt, Bernd
T1  - Orthogonal arylation of a diene-sulfonamide using cationic transition metal catalysts
JF  - European journal of organic chemistry
N2  - The regioselectivity of two mechanistically distinct alkenylation reactions catalyzed by in situ-formed cationic transition metal complexes was studied using 
N-allyl-N-phenylethenesulfonamide as a model compound. 
Orthogonal selectivity was observed for the Ru-catalyzed C-H-activating alkenylation with acetanilides, which occurs preferentially at the electron deficient double bond, and for a Pd-catalyzed Heck-type coupling with arene diazonium salts, which occurs preferentially at the more electron rich double bond of the N-allyl substituent.
KW  - arenes
KW  - C-H activation
KW  - palladium
KW  - ruthenium
KW  - sulfonamides
Y1  - 2022
U6  - https://doi.org/10.1002/ejoc.202201336
SN  - 1434-193X
SN  - 1099-0690
VL  - 2022
IS  - 47
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Prüfert, Christian
A1  - Beitz, Toralf
A1  - Reich, Olaf
A1  - Löhmannsröben, Hans-Gerd
T1  - Inline process analysis of copper-bearing aerosols using laser-induced breakdown spectroscopy, laser-induced incandescence and optical imaging
JF  - Spectrochimica acta, Part B, Atomic spectroscopy
N2  - The quantification and identification of aerosols in industry plays a key role in process monitoring and control and lays the foundation for process automation aspired by the industry 4.0 initiative. 
However, measuring particulate matter's mass and number concentrations in harsh environments poses great analytical constraints. 
The presented approach comprises a comprehensive set of light-and imaging-based techniques, all contactless, in-line, and real-time. It includes, but is not limited to, stroboscopic imaging, laser-induced breakdown spectroscopy (LIBS) and laser-induced incandescence (LII). Stroboscopic imaging confirmed the particles sphericity and was used to measure the particle number density. A phase-selective LIBS setup with low fluence and 500 Hz repetition rate was used to classify each particle with a single-pulse and in real time. Simultaneously, the created plasma was captured by CCD imaging to determine the detection volume and hit rate of the LIBS setup. 
Both data sets combined were converted to a particle number density, which was consistent with the particle number density of the stroboscopic measurements. Furthermore, using a photodiode and microphone in parallel to the LIBS setup allowed for the photoacoustic normalization of the spectral line intensity at the laser repetition rate of 500 Hz. 
This was done as a partial photoacoustic normalization method with the cut-off based on the coefficient of variation (CV), reducing it by 25%. Aside from that photodiode and microphone were proven to be valuable event counting with the advantage of the less spatially constricted. A second laser setup was used for laser -induced incandescence (LII) making it possible to classify the particles based on their incandescence tendency. Given its larger probing volume, LII could be employed at very low particle number densities. 
With respect to the current literature, this is the first approach of using LII as an in-line, real-time analytical technique for the compositional classification of metal-bearing aerosols.
KW  - LIBS
KW  - LII
KW  - aerosol. photoacoustics
KW  - stroboscopic imaging
KW  - minerals
Y1  - 2022
U6  - https://doi.org/10.1016/j.sab.2022.106527
SN  - 0584-8547
SN  - 1873-3565
VL  - 197
PB  - Elsevier
CY  - Amsterdam [u.a.]
ER  - 
TY  - JOUR
A1  - Wessig, Pablo
A1  - Badetko, Dominik
A1  - Koebe, Michael
T1  - Triplet sensitized Photo-Dehydro-Diels-Alder reaction
JF  - ChemistrySelect
N2  - We report on the triplet sensitization of the intramolecular Photo-Dehydro-Diels-Alder (PDDA) reaction of two diaryl suberates bearing methyl propiolate chromophors. Compared with the non-sensitized irradiation, considerably increased yields could be observed. 
Moreover, it is possible to use the more efficient UVA lamps instead of UVB lamps. 
Among three investigated sensitizers (xanthone, benzophenone, thioxanthone) xanthone gave the best results.
KW  - light sources
KW  - photochemistry
KW  - photodehydro-Diels-Alder reaction
KW  - triplet sensitization
Y1  - 2022
U6  - https://doi.org/10.1002/slct.202202648
SN  - 2365-6549
VL  - 7
IS  - 38
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Ebel, Kenny
A1  - Bald, Ilko
T1  - Low-energy (5-20 eV) electron-induced single and double strand breaks in well-defined DNA sequences
JF  - Journal of physical chemistry letters
N2  - Ionizing radiation is used in cancer radiation therapy to effectively damage the DNA of tumors. The main damage is due to generation of highly reactive secondary species such as low-energy electrons (LEEs). The accurate quantification of DNA radiation damage of well-defined DNA target sequences in terms of absolute cross sections for LEE-induced DNA strand breaks is possible by the DNA origami technique; however, to date, it is possible only for DNA single strands. In the present work DNA double strand breaks in the DNA sequence 5 '-d(CAC)4/5 ' d(GTG)4 are compared with DNA single strand breaks in the oligonucleotides 5 '-d(CAC)4 and 5 '-d(GTG)4 upon irradiation with LEEs in the energy range from 5 to 20 eV. A maximum of strand break cross section was found around 7 and 10 eV independent of the DNA sequence, indicating that dissociative electron attachment is the underlying mechanism of strand breakage and confirming previous studies using plasmid DNA.
Y1  - 2022
U6  - https://doi.org/10.1021/acs.jpclett.2c00684
SN  - 1948-7185
VL  - 13
IS  - 22
SP  - 4871
EP  - 4876
PB  - American Chemical Society
CY  - Washington, DC
ER  - 
TY  - THES
A1  - Martin, Johannes
T1  - Synthesis of protein-polymer conjugates and block copolymers via sortase-mediated ligation
N2  - In den vergangenen Jahrzehnten haben therapeutische Proteine in der pharmazeutischen Industrie mehr und mehr an Bedeutung gewonnen. Werden Proteine nichtmenschlichen Ursprungs verwendet, kann es jedoch zu einer Immunreaktion kommen, sodass das Protein sehr schnell aus dem Körper ausgeschieden oder abgebaut wird. Um die Zirkulationszeit im Blut signifikant zu verlängern, werden die Proteine mit synthetischen Polymeren modifiziert (Protein-Polymer-Konjugate). Die Proteine aller heute auf dem Markt erhältlichen Medikamente dieser Art tragen eine oder mehrere Polymerketten aus Poly(ethylenglycol) (PEG). Ein Nachteil der PEGylierung ist, dass viele Patienten bei regelmäßiger Einnahme dieser Medikamente Antikörper gegen PEG entwickeln, die den effizienzsteigernden Effekt der PEGylierung wieder aufheben.
Ein weiterer Nachteil der PEGylierung ist die oftmals deutlich verringerte Aktivität der Konjugate im Vergleich zum nativen Protein. Der Grund dafür ist die Herstellungsmethode der Konjugate, bei der meist die primären Amine der Lysin-Seitenketten und der N-Terminus des Proteins genutzt werden. Da die meisten Proteine mehrere gut zugängliche Lysine aufweisen, werden oft unterschiedliche und teilweise mehrere Lysine mit PEG funktionalisiert, was zu einer Mischung an Regioisomeren führt. Je nach Position der PEG-Kette kann das aktive Zentrum abgeschirmt oder die 3D-Struktur des Proteins verändert werden, was zu einem teilweise drastischen Aktivitätsabfall führt.
In dieser Arbeit wurde eine neuartige Methode zur Ligation von Makromolekülen untersucht. Die Verwendung eines Enzyms als Katalysator zur Verbindung zweier Makromoleküle ist bisher wenig untersucht und ineffizient. Als Enzym wurde Sortase A ausgewählt, eine gut untersuchte Ligase aus der Familie der Transpeptidasen, welche die Ligation zweier Peptide katalysieren kann.
Ein Nachteil dieser Sortase-vermittelten Ligation ist, dass es sich um eine Gleichgewichtsreaktion handelt, wodurch hohe Ausbeuten schwierig zu erreichen sind. Im Rahmen dieser Dissertation wurden zwei zuvor entwickelte Methoden zur Verschiebung des Gleichgewichts ohne Einsatz eines großen Überschusses von einem Edukt für Makromoleküle überprüft. 
Zur Durchführung der Sortase-vermittelten Ligation werden zwei komplementäre Peptidsequenzen verwendet, die Erkennungssequenz und das Nukleophil. Um eine systematische Untersuchung durchführen zu können, wurden alle nötigen Bausteine (Protein-Erkennungssequenz zur Reaktion mit Nukleophil-Polymer und Polymer-Erkennungssequenz mit Nukleophil-Protein) hergestellt. Als Polymerisationstechnik wurde die radikalische Polymerisation mit reversibler Deaktivierung (im Detail, Atom Transfer Radical Polymerization, ATRP und Reversible Addition-Fragmentation Chain Transfer, RAFT polymerization) gewählt, um eine enge Molmassenverteilung zu erreichen. 
Die Herstellung der Bausteine begann mit der Synthese der Peptide via automatisierter Festphasen-Peptidsynthese, um eine einfache Änderung der Peptidsequenz zu gewährleisten und um eine Modifizierung der Polymerkette nach der Polymerisation zu umgehen. Um die benötigte unterschiedliche Funktionalität der zwei Peptidsequenzen (freier C-Terminus bei der Erkennungssequenz bzw. freier N-Terminus bei dem Nukleophil) zu erreichen, wurden verschiedene Linker zwischen Harz und Peptid verwendet. Danach wurde der Kettenüberträger (chain transfer agent, CTA) zur Kontrolle der Polymerisation mit dem auf dem Harz befindlichen Peptid gekoppelt. Die für die anschließende Polymerisation verwendeten Monomere basierten auf Acrylamiden und Acrylaten und wurden anhand ihrer Eignung als Alternativen zu PEG ausgewählt. Es wurde eine kürzlich entwickelte Technik basierend auf der RAFT-Polymerisation (xanthate-supported photo-iniferter RAFT, XPI-RAFT) verwendet um eine Reihe an Peptid-Polymeren mit unterschiedlichen Molekulargewichten und engen Molekulargewichtsverteilungen herzustellen. Nach Entfernung der Schutzgruppen der Peptid-Seitenketten wurden die Peptid-Polymere zunächst genutzt, um mittels Sortase-vermittelter Ligation zwei Polymerketten zu einem Blockcopolymer zu verbinden. Unter Verwendung von Ni2+-Ionen in Kombination mit einer Verlängerung der Erkennungssequenz um ein Histidin zur Unterdrückung der Rückreaktion konnte ein maximaler Umsatz von 70 % erreicht werden. Dabei zeigte sich ein oberes Limit von durchschnittlich 100 Wiederholungseinheiten; die Ligation von längeren Polymeren war nicht erfolgreich. 
Danach wurden ein Modellprotein und ein Nanobody mit vielversprechenden medizinischen Eigenschaften mit den für die enzymkatalysierte Ligation benötigten Peptidsequenzen für die Kopplung mit den zuvor hergestellten Peptid-Polymeren verwendet. Dabei konnte bei Verwendung des Modellproteins keine Bildung von Protein-Polymer-Konjugaten beobachtet werden.
Der Nanobody konnte dagegen C-terminal mit einem Polymer funktionalisiert werden. Dabei wurde eine ähnliche Limitierung in der Polymer-Kettenlänge beobachtet wie zuvor. Die auf Ni-Ionen basierte Strategie zur Gleichgewichtsverschiebung hatte hier keinen ausschlaggebenden Effekt, während die Verwendung von einem Überschuss an Polymer zur vollständigen Umsetzung des Edukt-Nanobody führte. 
Die erhaltenen Daten aus diesem Projekt bilden eine gute Basis für weitere Forschung in dem vielversprechenden Feld der enzymkatalysierten Herstellung von Protein-Polymer-Konjugaten und Blockcopolymeren. Langfristig könnte diese Herangehensweise eine vielseitig einsetzbare Herstellungsmethode von ortsspezifischen therapeutischen Protein-Polymer Konjugaten darstellen, welche sowohl eine hohe Aktivität als auch eine lange Zirkulationszeit im Blut aufweisen.
N2  - During the last decades, therapeutical proteins have risen to great significance in the pharmaceutical industry. As non-human proteins that are introduced into the human body cause a distinct immune system reaction that triggers their rapid clearance, most newly approved protein pharmaceuticals are shielded by modification with synthetic polymers to significantly improve their blood circulation time. All such clinically approved protein-polymer conjugates contain polyethylene glycol (PEG) and its conjugation is denoted as PEGylation. However, many patients develop anti-PEG antibodies which cause a rapid clearance of PEGylated molecules upon repeated administration. Therefore, the search for alternative polymers that can replace PEG in therapeutic applications has become important. In addition, although the blood circulation time is significantly prolonged, the therapeutic activity of some conjugates is decreased compared to the unmodified protein. The reason is that these conjugates are formed by the traditional conjugation method that addresses the protein's lysine side chains. As proteins have many solvent exposed lysines, this results in a somewhat uncontrolled attachment of polymer chains, leading to a mixture of regioisomers, with some of them eventually affecting the therapeutic performance. 
This thesis investigates a novel method for ligating macromolecules in a site-specific manner, using enzymatic catalysis. Sortase A is used as the enzyme: It is a well-studied transpeptidase which is able to catalyze the intermolecular ligation of two peptides. This process is commonly referred to as sortase-mediated ligation (SML). SML constitutes an equilibrium reaction, which limits product yield. Two previously reported methods to overcome this major limitation were tested with polymers without using an excessive amount of one reactant.
Specific C- or N-terminal peptide sequences (recognition sequence and nucleophile) as part of the protein are required for SML. The complementary peptide was located at the polymer chain end. Grafting-to was used to avoid damaging the protein during polymerization. To be able to investigate all possible combinations (protein-recognition sequence and nucleophile-protein as well as polymer-recognition sequence and nucleophile-polymer) all necessary building blocks were synthesized. Polymerization via reversible deactivation radical polymerization (RDRP) was used to achieve a narrow molecular weight distribution of the polymers, which is required for therapeutic use.
The synthesis of the polymeric building blocks was started by synthesizing the peptide via automated solid-phase peptide synthesis (SPPS) to avoid post-polymerization attachment and to enable easy adaptation of changes in the peptide sequence. To account for the different functionalities (free N- or C-terminus) required for SML, different linker molecules between resin and peptide were used.
To facilitate purification, the chain transfer agent (CTA) for reversible addition-fragmentation chain-transfer (RAFT) polymerization was coupled to the resin-immobilized recognition sequence peptide. The acrylamide and acrylate-based monomers used in this thesis were chosen for their potential to replace PEG.
Following that, surface-initiated (SI) ATRP and RAFT polymerization were attempted, but failed. As a result, the newly developed method of xanthate-supported photo-iniferter (XPI) RAFT polymerization in solution was used successfully to obtain a library of various peptide-polymer conjugates with different chain lengths and narrow molar mass distributions. 
After peptide side chain deprotection, these constructs were used first to ligate two polymers via SML, which was successful but revealed a limit in polymer chain length (max. 100 repeat units). When utilizing equimolar amounts of reactants, the use of Ni2+ ions in combination with a histidine after the recognition sequence to remove the cleaved peptide from the equilibrium maximized product formation with conversions of up to 70 %.
Finally, a model protein and a nanobody with promising properties for therapeutical use were biotechnologically modified to contain the peptide sequences required for SML. Using the model protein for C- or N-terminal SML with various polymers did not result in protein-polymer conjugates. The reason is most likely the lack of accessibility of the protein termini to the enzyme. Using the nanobody for C-terminal SML, on the other hand, was successful. However, a similar polymer chain length limit was observed as in polymer-polymer SML. Furthermore, in case of the synthesis of protein-polymer conjugates, it was more effective to shift the SML equilibrium by using an excess of polymer than by employing the Ni2+ ion strategy.
Overall, the experimental data from this work provides a good foundation for future research in this promising field; however, more research is required to fully understand the potential and limitations of using SML for protein-polymer synthesis. In future, the method explored in this dissertation could prove to be a very versatile pathway to obtain therapeutic protein-polymer conjugates that exhibit high activities and long blood circulation times.
KW  - biohybrid molecules
KW  - sortaseA
KW  - polymerization
KW  - RAFT
KW  - ATRP
KW  - peptide synthesis
KW  - enzymatic conjugation
KW  - sortagging
Y1  - 2024
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-645669
ER  - 
TY  - CHAP
A1  - Wang, Zhenyu
A1  - Breternitz, Joachim
A1  - Schorr, Susan
T1  - Cation disorder in zinc-group IV- nitride and oxide nitride semiconductor materials revealed through neutron diffraction
T2  - Acta crystallographica / International Union of Crystallography. Section A, Foundations and advances
KW  - nitride materials
KW  - semiconductors
KW  - structure-property relationships
Y1  - 2021
U6  - https://doi.org/10.1107/S0108767321086256
SN  - 2053-2733
VL  - 77
IS  - Suppl.
SP  - C1077
EP  - C1077
PB  - Blackwell
CY  - Oxford [u.a.]
ER  - 
TY  - JOUR
A1  - Erler, Alexander
A1  - Riebe, Daniel
A1  - Beitz, Toralf
A1  - Löhmannsröben, Hans-Gerd
A1  - Leenen, Mathias
A1  - Pätzold, Stefan
A1  - Ostermann, Markus
A1  - Wójcik, Michał
T1  - Mobile laser-induced breakdown spectroscopy for future application in precision agriculture
BT  - a case study
JF  - Sensors
N2  - In precision agriculture, the estimation of soil parameters via sensors and the creation of nutrient maps are a prerequisite for farmers to take targeted measures such as spatially resolved fertilization. In this work, 68 soil samples uniformly distributed over a field near Bonn are investigated using laser-induced breakdown spectroscopy (LIBS). These investigations include the determination of the total contents of macro- and micronutrients as well as further soil parameters such as soil pH, soil organic matter (SOM) content, and soil texture. The applied LIBS instruments are a handheld and a platform spectrometer, which potentially allows for the single-point measurement and scanning of whole fields, respectively. Their results are compared with a high-resolution lab spectrometer. The prediction of soil parameters was based on multivariate methods. Different feature selection methods and regression methods like PLS, PCR, SVM, Lasso, and Gaussian processes were tested and compared. While good predictions were obtained for Ca, Mg, P, Mn, Cu, and silt content, excellent predictions were obtained for K, Fe, and clay content. The comparison of the three different spectrometers showed that although the lab spectrometer gives the best results, measurements with both field spectrometers also yield good results. This allows for a method transfer to the in-field measurements.
KW  - LIBS
KW  - precision agriculture
KW  - soil
KW  - multivariate methods
KW  - feature selection
Y1  - 2023
U6  - https://doi.org/10.3390/s23167178
SN  - 1424-8220
VL  - 23
IS  - 16
PB  - MDPI
CY  - Basel
ER  - 
TY  - JOUR
A1  - Adesina, Morenike O.
A1  - Block, Inga
A1  - Günter, Christina
A1  - Unuabonah, Emmanuel Iyayi
A1  - Taubert, Andreas
T1  - Efficient Removal of Tetracycline and Bisphenol A from Water with a New Hybrid Clay/TiO₂ Composite
JF  - ACS Omega
N2  - New TiO₂ hybrid composites were prepared fromkaolinclay, predried and carbonized biomass, and titanium tetraisopropoxideand explored for tetracycline (TET) and bisphenol A (BPA) removalfrom water. Overall, the removal rate is 84% for TET and 51% for BPA.The maximum adsorption capacities (q (m))are 30 and 23 mg/g for TET and BPA, respectively. These capacitiesare far greater than those obtained for unmodified TiO2. Increasing the ionic strength of the solution does not change theadsorption capacity of the adsorbent. pH changes only slightly changeBPA adsorption, while a pH > 7 significantly reduces the adsorptionof TET on the material. The Brouers-Sotolongo fractal modelbest describes the kinetic data for both TET and BPA adsorption, predictingthat the adsorption process occurs via a complex mechanism involvingvarious forces of attraction. Temkin and Freundlich isotherms, whichbest fit the equilibrium adsorption data for TET and BPA, respectively,suggest that adsorption sites are heterogeneous in nature. Overall,the composite materials are much more effective for TET removal fromaqueous solution than for BPA. This phenomenon is assigned to a differencein the TET/adsorbent interactions vs the BPA/adsorbent interactions:the decisive factor appears to be favorable electrostatic interactionsfor TET yielding a more effective TET removal.
Y1  - 2023
U6  - https://doi.org/10.1021/acsomega.3c00184
SN  - 2470-1343
VL  - 8
IS  - 24
SP  - 21594
EP  - 21604
PB  - American Chemical Society
CY  - Washington
ER  - 
TY  - JOUR
A1  - Mazarei, Elham
A1  - Penschke, Christopher
A1  - Saalfrank, Peter
T1  - Band gap engineering in two-dimensional materials by functionalization
BT  - Methylation of graphene and graphene bilayers
JF  - ACS Omega
N2  - Graphene is well-knownfor its unique combination of electricaland mechanical properties. However, its vanishing band gap limitsthe use of graphene in microelectronics. Covalent functionalizationof graphene has been a common approach to address this critical issueand introduce a band gap. In this Article, we systematically analyzethe functionalization of single-layer graphene (SLG) and bilayer graphene(BLG) with methyl (CH3) using periodic density functionaltheory (DFT) at the PBE+D3 level of theory. We also include a comparisonof methylated single-layer and bilayer graphene, as well as a discussionof different methylation options (radicalic, cationic, and anionic).For SLG, methyl coverages ranging from 1/8 to 1/1, (i.e.,the fully methylated analogue of graphane) are considered. We findthat up to a coverage theta of 1/2, graphene readily accepts CH3, with neighbor CH3 groups preferring trans positions. Above theta = 1/2, the tendency to accept further CH3 weakens and the lattice constant increases. The band gapbehaves less regularly, but overall it increases with increasing methylcoverage. Thus, methylated graphene shows potential for developingband gap-tuned microelectronics devices and may offer further functionalizationoptions. To guide in the interpretation of methylation experiments,vibrational signatures of various species are characterized by normal-modeanalysis (NMA), their vibrational density of states (VDOS), and infrared(IR) spectra, the latter two are obtained from ab initio moleculardynamics (AIMD) in combination with a velocity-velocity autocorrelationfunction (VVAF) approach.
KW  - Adsorption
KW  - Alkyls
KW  - Band structure
KW  - Electrical conductivity
KW  - Two dimensional materials
Y1  - 2023
U6  - https://doi.org/10.1021/acsomega.3c02068
SN  - 2470-1343
VL  - 8
IS  - 24
SP  - 22026
EP  - 22041
PB  - American Chemical Society
CY  - Washington
ER  - 
TY  - JOUR
A1  - Kleinpeter, Erich
A1  - Koch, Andreas
T1  - The multiple bond character of the carbon-boron bond in boron trapped N-heterocyclic carbenes (NHCs) and cyclic(alkyl)(amino) carbenes (CAACs) on the magnetic criterion
JF  - Tetrahedron
N2  - Geometry, 11B, 13C chemical shifts and the spatial magnetic properties (Through-Space NMR Shieldings -TSNMRS) of both cations and anions of boron-trapped N-heterocyclic carbenes (NHCs) and cyclic (alkyl)(amino)carbenes (CAACs) and of the corresponding diborane/diborene/diboryne dis-carbene adducts have been calculated using the GIAO perturbation method employing the nucleus independent chemical shift (NICS) concept; the TSNMRS results are visualized as iso-chemical-shielding surfaces (ICSS) of various size and direction. The ICSS of the TSNMRS (actually the anisotropy effects measurable in 1H NMR spectroscopy) are employed to qualify and quantify the present multiple bond character of the Carbene-Boron bond in the trapped NHCs and CAACs. Results are confirmed by bond length and 11B/13C chemical shift variations. Thus the partial multiple bond character of the Carbene-Boron bond cannot be expressed by the arrow of weak, much longer dative bonds and should be omitted as in other covalent lone pair-it or triel bonds. & COPY; 2023 Elsevier Ltd. All rights reserved.
KW  - NHCs
KW  - CAACs
KW  - Multiple NHC(CAAC)-Boron bonds
KW  - Through -space NMR
KW  - shieldings (TSNMRS)
KW  - NICS
KW  - Anisotropy effect
KW  - Ring current effect
Y1  - 2023
U6  - https://doi.org/10.1016/j.tet.2023.133469
SN  - 0040-4020
SN  - 1464-5416
VL  - 140
PB  - Elsevier
CY  - Oxford
ER  - 
TY  - JOUR
A1  - Schlappa, Stephanie
A1  - Bressel, Lena
A1  - Reich, Oliver
A1  - Münzberg, Marvin
T1  - Advanced particle size analysis in high-solid-content polymer dispersions using photon density wave spectroscopy
JF  - Polymers
N2  - High-solid-content polystyrene and polyvinyl acetate dispersions of polymer particles with a 50 nm to 500 nm mean particle diameter and 12-55% (w/w) solid content have been produced via emulsion polymerization and characterized regarding their optical and physical properties. Both systems have been analyzed with common particle-size-measuring techniques like dynamic light scattering (DLS) and static light scattering (SLS) and compared to inline particle size distribution (PSD) measurements via photon density wave (PDW) spectroscopy in undiluted samples. It is shown that particle size measurements of undiluted polystyrene dispersions are in good agreement between analysis methods. However, for polyvinyl acetate particles, size determination is challenging due to bound water in the produced polymer. For the first time, water-swelling factors were determined via an iterative approach of PDW spectroscopy error (X-2) minimization. It is shown that water-swollen particles can be analyzed in high-solid-content solutions and their physical properties can be assumed to determine the refractive index, density, and volume fraction in dispersion. It was found that assumed water swelling improved the reduced scattering coefficient fit by PDW spectroscopy by up to ten times and particle size determination was refined and enabled. Particle size analysis of the water-swollen particles agreed well with offline-based state-of-the-art techniques.
KW  - emulsion polymerization
KW  - multiple light scattering
KW  - photon density wave
KW  - spectroscopy
KW  - particle sizing
KW  - swelling of polymers
Y1  - 2023
U6  - https://doi.org/10.3390/polym15153181
SN  - 2073-4360
VL  - 15
IS  - 15
PB  - MDPI
CY  - Basel
ER  - 
TY  - JOUR
A1  - Xu, Yaolin
A1  - Dong, Kang
A1  - Jie, Yulin
A1  - Adelhelm, Philipp
A1  - Chen, Yawei
A1  - Xu, Liang
A1  - Yu, Peiping
A1  - Kim, Junghwa
A1  - Kochovski, Zdravko
A1  - Yu, Zhilong
A1  - Li, Wanxia
A1  - LeBeau, James
A1  - Shao-Horn, Yang
A1  - Cao, Ruiguo
A1  - Jiao, Shuhong
A1  - Cheng, Tao
A1  - Manke, Ingo
A1  - Lu, Yan
T1  - Promoting mechanistic understanding of lithium deposition and solid-electrolyte interphase (SEI) formation using advanced characterization and simulation methods: recent progress, limitations, and future perspectives
JF  - Avanced energy materials
N2  - In recent years, due to its great promise in boosting the energy density of lithium batteries for future energy storage, research on the Li metal anode, as an alternative to the graphite anode in Li-ion batteries, has gained significant momentum. However, the practical use of Li metal anodes has been plagued by unstable Li (re)deposition and poor cyclability. Although tremendous efforts have been devoted to the stabilization of Li metal anodes, the mechanisms of electrochemical (re-)deposition/dissolution of Li and solid-electrolyte-interphase (SEI) formation remain elusive. This article highlights the recent mechanistic understandings and observations of Li deposition/dissolution and SEI formation achieved from advanced characterization techniques and simulation methods, and discusses major limitations and open questions in these processes. In particular, the authors provide their perspectives on advanced and emerging/potential methods for obtaining new insights into these questions. In addition, they give an outlook into cutting-edge interdisciplinary research topics for Li metal anodes. It pushes beyond the current knowledge and is expected to accelerate development toward a more in-depth and comprehensive understanding, in order to guide future research on Li metal anodes toward practical application.
KW  - advanced characterization
KW  - Li deposition
KW  - Li dissolution
KW  - Li metal
KW  - anodes
KW  - mechanistic understanding
KW  - solid-electrolyte-interphase
KW  - theoretical simulation
Y1  - 2022
U6  - https://doi.org/10.1002/aenm.202200398
SN  - 1614-6832
SN  - 1614-6840
VL  - 12
IS  - 19
PB  - Wiley
CY  - Weinheim
ER  - 
TY  - THES
A1  - Heinz, Markus
T1  - Synthese von Monomeren auf der Basis nachwachsender Rohstoffe und ihre Polymerisation
T1  - Synthesis of Monomers based on Renewable Resources and their Polymerization
N2  - Die vorliegende Arbeit thematisiert die Synthese und die Polymerisation von Monomeren auf der Basis nachwachsender Rohstoffe wie zum Beispiel in Gewürzen und ätherischen Ölen enthaltenen kommerziell verfügbaren Phenylpropanoiden (Eugenol, Isoeugenol, Zimtalkohol, Anethol und Estragol) und des Terpenoids Myrtenol sowie ausgehend von der Rinde einer Birke (Betula pendula) und der Korkeiche (Quercus suber). Ausgewählte Phenylpropanoide (Eugenol, Isoeugenol und Zimtalkohol) und das Terpenoid Myrtenol wurden zunächst in den jeweiligen Laurylester überführt und anschließend das olefinische Strukturelement epoxidiert, wobei 4 neue (2-Methoxy-4-(oxiran-2-ylmethyl)phenyldodecanoat, 2-Methoxy-4-(3-methyl-oxiran-2-yl)phenyldodecanoat, (3-Phenyloxiran-2-yl)methyldodecanoat, (7,7-Dimethyl-3-oxatricyclo[4.1.1.02,4]octan-2-yl)methyldodecanoat) und 2 bereits bekannte monofunktionelle Epoxide (2-(4-Methoxybenzyl)oxiran und 2-(4-Methoxyphenyl)-3-methyloxiran) erhalten wurden, die mittels 1H-NMR-, 13C-NMR- und FT-IR-Spektroskopie sowie mit DSC untersucht wurden. Die Photo-DSC Untersuchung der Epoxidmonomere in einer kationischen Photopolymerisation bei 40 °C ergab die maximale Polymerisationsgeschwindigkeit (Rpmax: 0,005 s-1 bis 0,038 s-1) sowie die Zeit (tmax: 13 s bis 26 s) bis zum Erreichen des Rpmax-Wertes und führte zu flüssigen Oligomeren, deren zahlenmittlerer Polymerisationsgrad mit 3 bis 6 mittels GPC bestimmt wurde. Die Umsetzung von 2-Methoxy-4-(oxiran-2-ylmethyl)phenyldodecanoat mit Methacrylsäure ergab ein Isomerengemisch (2-Methoxy-4-(2-hydroxy-3-(methacryloyloxy)propyl)phenyldodecanoat und 2-Methoxy-4-(2-(methacryl-oyloxy)-3-hydroxypropyl)phenyldodecanoat), das mittels Photo-DSC in einer freien radikalischen Photopolymerisation untersucht wurde (Rpmax: 0,105 s-1 und tmax: 5 s), die zu festen in Chloroform unlöslichen Polymeren führte.

Aus Korkpulver und gemahlener Birkenrinde wurden selektiv 2 kristalline ω-Hydroxyfettsäuren (9,10-Epoxy-18-hydroxyoctadecansäure und 22-Hydroxydocosansäure) isoliert. Die kationische Photopolymerisation der 9,10-Epoxy-18-hydroxyoctadecansäure ergab einen nahezu farblosen transparenten und bei Raumtemperatur elastischen Film, welcher ein Anwendungspotential für Oberflächenbeschichtungen hat. Aus der Reaktion von 9,10-Epoxy-18-hydroxyoctadecansäure mit Methacrylsäure wurde ein bei Raumtemperatur flüssiges Gemisch aus zwei Konstitutionsisomeren (9,18-Dihydroxy-10-(methacryloyloxy)octadecansäure und 9-(Methacryloyloxy)-10,18-dihydroxyoctadecansäure) erhalten (Tg: -60 °C). Die radikalische Photopolymerisation dieser Konstitutionsisomere wurde ebenfalls mittels Photo-DSC untersucht (Rpmax: 0,098 s-1 und tmax: 3,8 s). Die Reaktion von 22-Hydroxydocosansäure mit Methacryloylchlorid ergab die kristalline 22-(Methacryloyloxy)docosansäure, welche ebenfalls in einer radikalischen Photopolymerisation mittels Photo-DSC untersucht wurde (Rpmax: 0,023 s-1 und tmax: 9,6 s).

Die mittels AIBN in Dimethylsulfoxid initiierte Homopolymerisation der 22-(Methacryloyloxy)docosansäure und der Isomerengemische bestehend aus 2-Methoxy-4-(2-hydroxy-3-(methacryloyloxy)propyl)phenyldodecanoat und 2-Methoxy-4-(2-(methacryl-oyloxy)-3-hydroxypropyl)phenyldodecanoat sowie aus 9,18-Dihydroxy-10-(methacryloy-loxy)octadecansäure und 9-(Methacryloyloxy)-10,18-dihydroxyoctadecansäure ergab feste lösliche Polymere, die mittels 1H-NMR- und FT-IR-Spektroskopie, GPC (Poly(2-methoxy-4-(2-hydroxy-3-(methacryloyloxy)propyl)phenyldodecanoat / 2-methoxy-4-(2-(methacryloyloxy)-3-hydroxypropyl)phenyldodecanoat): Pn = 94) und DSC (Poly(2-methoxy-4-(2-hydroxy-3-(methacryloyloxy)propyl)phenyldodecanoat / 2-methoxy-4-(2-(methacryloyloxy)-3-hydroxypropyl)phenyldodecanoat): Tg: 52 °C; Poly(9,18-dihydroxy-10-(methacryloyloxy)-octadecansäure / 9-(methacryloyloxy)-10,18-dihydroxyoctadecansäure): Tg: 10 °C; Poly(22-(methacryloyloxy)docosansäure): Tm: 74,1 °C, wobei der Schmelzpunkt mit dem des Photopolymers (Tm = 76,8 °C) vergleichbar ist) charakterisiert wurden.

Das bereits bekannte Monomer 4-(4-Methacryloyloxyphenyl)butan-2-on wurde ausgehend von 4-(4-Hydroxyphenyl)butan-2-on hergestellt, welches aus Birkenrinde gewonnen werden kann, und unter identischen Bedingungen für einen Vergleich mit den neuen Monomeren polymerisiert. Die freie radikalische Polymerisation führte zu Poly(4-(4-methacryloyloxyphenyl)butan-2-on) (Pn: 214 und Tg: 83 °C). Neben der Homopolymerisation wurde eine statistische Copolymerisation des Isomerengemisches 2-Methoxy-4-(2-hydroxy-3-(methacryl-oyloxy)propyl)phenyldodecanoat / 2-Methoxy-4-(2-(methacryloyloxy)-3-hydroxypropyl)-phenyldodecanoat mit 4-(4-Methacryloyloxyphenyl)butan-2-on untersucht, wobei ein äquimolarer Einsatz der Ausgangsmonomere zu einem Anstieg der Ausbeute, der Molmassenverteilung und der Dispersität des Copolymers (Tg: 44 °C) führte. Die unter Verwendung von Diethylcarbonat als „grünes“ Lösungsmittel mittels AIBN initiierten freien radikalischen Homopolymerisationen von 4-(4-Methacryloyloxyphenyl)butan-2-on und von Laurylmethacrylat ergaben vergleichbare Polymerisationsgrade der Homopolymere (Pn: 150), welche jedoch aufgrund ihrer Strukturunterschiede deutlich unterschiedliche Glasübergangstemperaturen hatten (Poly(4-(4-methacryloyloxyphenyl)butan-2-on): Tg: 70 °C, Poly(laurylmethacrylat) Tg: -49 °C. Eine statistische Copolymerisation äquimolarer Stoffmengen der beiden Monomere in Diethylcarbonat führte bei einer Polymerisationszeit von 60 Minuten zu einem leicht bevorzugten Einbau des 4-(4-Methacryloyloxyphenyl)butan-2-on in das Copolymer (Tg: 17 °C). Copolymerisationsdiagramme für die freien radikalischen Copolymerisationen von 4-(4-Methacryloyloxyphenyl)butan-2-on mit n-Butylmethacrylat beziehungsweise 2-(Dimethylamino)ethylmethacrylat (t: 20 min bis 60 min; Molenbrüche (X) für 4-(4-Methacryloyloxyphenyl)butan-2-on: 0,2; 0,4; 0,6 und 0,8) zeigten ein nahezu ideales azeotropes Copolymerisationsverhalten, obwohl ein leicht bevorzugter Einbau von 4-(4-Methacryloyloxyphenyl)butan-2-on in das jeweilige Copolymer beobachtet wurde. Dabei korreliert ein Anstieg der Ausbeute und der Glasübergangstemperatur der erhaltenen Copolymere mit einem zunehmenden Gehalt an 4-(4-Methacryloyloxyphenyl)butan-2-on im Reaktionsgemisch. Die unter Einsatz der modifizierten Gibbs-DiMarzio-Gleichung berechneten Glasübergangstemperaturen der Copolymere stimmten mit den gemessenen Werten gut überein. Das ist eine gute Ausgangsbasis für die Bestimmung der Glasübergangstemperatur eines Copolymers mit einer beliebigen Zusammensetzung.
N2  - The subject of this work is the synthesis and polymerization of monomers based on renewable material e. g. commercially available phenylpropanoides (eugenol, iso-eugenol, cinnamyl alcohol, anethol, and estragol) containing in spices and essential oils, the terpenoid myrtenol, as well as material derived from the bark of a birch (Betula pendula) and cork oak (Quercus suber). Selected phenylpropanoides (eugenol, iso-eugenol and cinnamyl alcohol) and the terpenoid myrtenol were first transferred to the lauryl ester followed by epoxidation of the olefinic structure to yield 4 new (2-methoxy-4-(oxiran-2-ylmethyl)-phenyl dodecanoate, 2-methoxy-4-(3-methyloxiran-2-yl)phenyl dodecanoate, (3-phenyloxiran-2-yl)methyl dodecanoate, (7,7-dimethyl-3-oxatricyclo[4.1.1.02,4]octan-2-yl)methyl dodecanoate) and 2 already known monofunctional epoxides (2-(4-methoxybenzyl)oxirane and 2-(4-methoxy-phenyl)-3-methyloxirane), which were investigated using 1H-NMR-, 13C-NMR- and FT-IR- spectroscopy, and DSC. Photo-DSC investigation of the cationic polymerization of the epoxy monomers at 40 °C revealed the maximum polymerization rate (Rpmax: 0,005 s-1 to 0,038 s-1) and the time (tmax: 13 s to 26 s) to obtain the Rpmax value. Liquid oligomers were obtained with a number average degree of polymerization between 3 and 6, as determined by GPC. The reaction of 2-methoxy-4-(oxiran-2-ylmethyl)phenyl dodecanoate with methacrylic acid resulted in a mixture of isomers (2-methoxy-4-(2-hydroxy-3-(methacryloyloxy)propyl)-phenyl dodecanoate and 2-methoxy-4-(2-(methacryloyloxy)-3-hydroxypropyl)phenyl dodecanoate). Free radical photopolymerization of this isomeric mixture, studied by photo-DSC (Rpmax: 0,105 s-1 and tmax: 5 s), resulted in solid polymers that were insoluble in chloroform.

Two crystalline ω-hydroxy fatty acids (9,10-epoxy-18-hydroxyoctadecanoic acid and 22-hydroxydocosanoic acid) were selectively isolated from cork powder and powdered birch bark. The cationic photopolymerization of 9,10-epoxy-18-hydroxyoctadecanoic acid resulted in a nearly colorless transparent film that was elastic at room temperature.  Therefore, it has an application potential in the manufacture of coatings. The reaction of 9,10-epoxy-18-hydroxyoctadecanoic acid with methacrylic acid resulted in a mixture of two constitutional isomers (9,18-dihydroxy-10-(methacryloyloxy)octadecanoic acid and 9-(methacryloyloxy)-10,18-dihydroxyoctadecanoic acid), which is liquid at room temperature (Tg: -60 °C).  The radical photopolymerization of these constitutional isomers was also studied by photo-DSC (Rpmax: 0,098 s-1 and tmax: 3,8 s). The reaction of 22-hydroxydocosanoic acid with methacryloyl chloride yielded crystalline 22-(methacryloyloxy)docosanoic acid, which was studied by photo-DSC in a radical photopolymerization (Rpmax: 0,023 s-1 and tmax: 9,6 s).

The homopolymerization of both 22-(methacryloyloxy)docosanoic acid and the isomeric mixtures consisting of 2-methoxy-4-(2-hydroxy-3-(methacryloyloxy)propyl)phenyl dodecanoate and 2-methoxy-4-(2-(methacryloyloxy)-3-hydroxypropyl)phenyl dodecanoat as well as 9,18-dihydroxy-10-(methacryloyloxy)octadecanoic acid and 9-(methacryloyloxy)-10,18-dihydroxyoctadecanoic acid resulted in solid soluble polymers, which were characterized by 1H-NMR- and FT-IR-spectroscopy, GPC (poly(2-methoxy-4-(2-hydroxy-3-(methacryloyloxy)propyl)phenyl dodecanoat / 2-methoxy-4-(2-(methacryloyloxy)-3-hydroxy-propyl)phenyl dodecanoate): Pn = 94), and DSC (poly(2-methoxy-4-(2-hydroxy-3-(methacryloyloxy)propyl)phenyl dodecanoate / 2-methoxy-4-(2-(methacryloyloxy)-3-hydroxy-propyl)phenyl dodecanoate): Tg: 52 °C; poly(9,18-dihydroxy-10-(methacryloyloxy)-octadecanoic acid / 9-(methacryloyloxy)-10,18-dihydroxyoctadecanoic acid): Tg: 10 °C; poly(22-(methacryloyloxy)docosanoic acid): Tm: 74,1 °C, this melting temperature is comparable to that of the photopolymer (Tm = 76,8 °C)).

The already known monomer 4-(4-methacryloyloxyphenyl)butane-2-one was synthesized from 4-(4-hydroxyphenyl)butan-2-one obtained from birch bark and polymerized under identical conditions for comparison with the new monomers. The free radical polymerization resulted in poly(4-(4-methacryloyloxyphenyl)butan-2-one) (Pn: 214 and Tg: 83 °C). Besides the homopolymerization, a random copolymerization of the 2-methoxy-4-(2-hydroxy-3-(methacryloyloxy)propyl)phenyl dodecanoate / 2-methoxy-4-(2-(methacryloyl-oxy)-3-hydroxypropyl)phenyl dodecanoate isomer mixture with 4-(4-methacryloyloxyphenyl)butan-2-one was also investigated, which resulted in an increase in the yield, molecular weight distribution and dispersity of the  copolymer (Tg: 44 °C) at a stoichiometric ratio of the monomers. The application of diethyl carbonate as „green“ solvent in the free radical homopolymerization of both 4-(4-methacryloyloxyphenyl)butan-2-one and  lauryl methacrylate initiated with AIBN resulted in a comparable degree of polymerization of the homopolymers obtained (Pn: 150). However, due to the structural differences of the monomer segments, different glass transition temperatures were obtained for poly(4-(4-methacryloyloxyphenyl)butan-2-one) (Tg: 70 °C) and poly(lauryl methacrylate) (Tg: -49 °C). A random copolymerization of a stoichiometric ratio of the monomers in diethyl carbonate resulted in a slightly preferential incorporation of the 4-(4-methacryloyloxyphenyl)butan-2-one in the copolymer (Tg: 17 °C) after a polymerization time of 60 min. Copolymerization diagrams for free radical copolymerizations of 4-(4-methacryloyloxyphenyl)butan-2-one with either n-butyl methacrylate or 2-(dimethylamino)ethyl methacrylate (t: 20 min to 60 min; molar fraction (X) for 4-(4-methacryloyloxyphenyl)butan-2-one: 0,2; 0,4; 0,6 and 0,8) showed an almost ideal azeotropic copolymerization behavior, although a slightly preferential incorporation of the 4-(4-methacryloyloxyphenyl)butan-2-one was observed in the copolymers. An increase in both yield and glass transition temperature of the copolymers obtained correlated with an increasing content on 4-(4-methacryloyloxyphenyl)butan-2-one in the reaction mixture. Good agreement was found between the glass transition temperatures calculated using the modified Gibbs-DiMarzio equation and the measured values for the copolymers. This is a good basis for determining the glass transition temperature of a copolymer of any composition.
KW  - photoinitiierte kationische Polymerisation
KW  - Epoxide
KW  - epoxidierte Phenylpropanoide
KW  - epoxidierte Terpene
KW  - Copolymerisationsdiagramme
KW  - freie radikalische Polymerisation
KW  - Glasübergangstemperaturen
KW  - Methacrylate
KW  - Molmassen
KW  - statistische Copolymere
KW  - 9,10-Epoxy-18-hydroxyoctadecansäure
KW  - biobasierte Methacrylate
KW  - biobasierte Monomere
KW  - nachwachsende Rohstoffe
KW  - 22-Hydroxydocosansäure
KW  - photoinitiierte Polymerisation
KW  - Polymerisation
KW  - Betula pendula
KW  - Quercus suber
KW  - Birke
KW  - Korkeiche
KW  - Biomasse
KW  - Birkenrinde
KW  - grüne Chemie
KW  - Polymere
KW  - photoinitiierte freie radikalische Polymerisation
KW  - 22-hydroxydocosanoic acid
KW  - 9,10-epoxy-18-hydroxyoctadecanoic acid
KW  - Betula pendula
KW  - biomass
KW  - birch
KW  - birch bark
KW  - copolymerization diagrams
KW  - Epoxides
KW  - Glass transition temperatures
KW  - Cork oak
KW  - Methacrylates
KW  - Molar masses
KW  - polymers
KW  - polymerization
KW  - Quercus suber
KW  - bio-based methacrylates
KW  - bio-based monomers
KW  - epoxidized phenylpropanoids
KW  - epoxidized terpenes
KW  - free radical polymerization
KW  - green chemistry
KW  - renewable raw materials
KW  - photoinitiated polymerization
KW  - photoinitiated free radical
KW  - photoinitiated cationic polymerization
KW  - random copolymers
KW  - photopolymerization
KW  - Baumrinde
KW  - Rinde
KW  - tree bark
KW  - bark
KW  - Photopolymerisation
Y1  - 2024
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-637943
ER  - 
TY  - JOUR
A1  - Rothe, Martin
A1  - Zhao, Yuhang
A1  - Müller, Johannes
A1  - Kewes, Günter
A1  - Koch, Christoph T.
A1  - Lu, Yan
A1  - Benson, Oliver
T1  - Self-assembly of plasmonic nanoantenna-waveguide structures for subdiffractional chiral sensing
JF  - ACS nano
N2  - Spin-momentum locking is a peculiar effect in the near-field of guided optical or plasmonic modes. It can be utilized to map the spinning or handedness of electromagnetic fields onto the propagation direction. This motivates a method to probe the circular dichroism of an illuminated chiral object. In this work, we demonstrate local, subdiffraction limited chiral coupling of light and propagating surface plasmon polaritons in a self-assembled system of a gold nanoantenna and a silver nanowire. A thin silica shell around the nanowire provides precise distance control and also serves as a host for fluorescent molecules, which indicate the direction of plasmon propagation. We characterize our nanoantenna-nanowire systems comprehensively through correlated electron microscopy, energy-dispersive X-ray spectroscopy, dark-field, and fluorescence imaging. Three-dimensional numerical simulations support the experimental findings. Besides our measurement of far-field polarization, we estimate sensing capabilities and derive not only a sensitivity of 1 mdeg for the ellipticity of the light field, but also find 10(3) deg cm(2)/dmol for the circular dichroism of an analyte locally introduced in the hot spot of the antenna-wire system. Thorough modeling of a prototypical design predicts on-chip sensing of chiral analytes. This introduces our system as an ultracompact sensor for chiral response far below the diffraction limit.
KW  - plasmonics
KW  - nanoparticle assemblies
KW  - core-shell
KW  - spin-orbit coupling
KW  - chirality
KW  - circular dichroism
KW  - nano-optics
Y1  - 2021
U6  - https://doi.org/10.1021/acsnano.0c05240
SN  - 1936-0851
SN  - 1936-086X
VL  - 15
IS  - 1
SP  - 351
EP  - 361
PB  - American Chemical Society
CY  - Washington
ER  - 
TY  - JOUR
A1  - Ning, Jiaoyi
A1  - Yu, Hongtao
A1  - Mei, Shilin
A1  - Schütze, Yannik
A1  - Risse, Sebastian
A1  - Kardjilov, Nikolay
A1  - Hilger, André
A1  - Manke, Ingo
A1  - Bande, Annika
A1  - Ruiz, Victor G.
A1  - Dzubiella, Joachim
A1  - Meng, Hong
A1  - Lu, Yan
T1  - Constructing binder- and carbon additive-free organosulfur cathodes based on conducting thiol-polymers through electropolymerization for lithium-sulfur batteries
JF  - ChemSusChem
N2  - Herein, the concept of constructing binder- and carbon additive-free organosulfur cathode was proved based on thiol-containing conducting polymer poly(4-(thiophene-3-yl) benzenethiol) (PTBT). The PTBT featured the polythiophene-structure main chain as a highly conducting framework and the benzenethiol side chain to copolymerize with sulfur and form a crosslinked organosulfur polymer (namely S/PTBT). Meanwhile, it could be in-situ deposited on the current collector by electro-polymerization, making it a binder-free and free-standing cathode for Li-S batteries. The S/PTBT cathode exhibited a reversible capacity of around 870 mAh g(-1) at 0.1 C and improved cycling performance compared to the physically mixed cathode (namely S&PTBT). This multifunction cathode eliminated the influence of the additives (carbon/binder), making it suitable to be applied as a model electrode for operando analysis. Operando X-ray imaging revealed the remarkable effect in the suppression of polysulfides shuttle via introducing covalent bonds, paving the way for the study of the intrinsic mechanisms in Li-S batteries.
KW  - electrochemistry
KW  - energy storage
KW  - lithium-sulfur batteries
KW  - operando
KW  - studies
KW  - organosulfur
Y1  - 2022
U6  - https://doi.org/10.1002/cssc.202200434
SN  - 1864-5631
SN  - 1864-564X
VL  - 15
IS  - 14
PB  - Wiley
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Lau, Skadi
A1  - Liu, Yue
A1  - Maier, Anna
A1  - Braune, Steffen
A1  - Gossen, Manfred
A1  - Neffe, Axel T.
A1  - Lendlein, Andreas
T1  - Establishment of an in vitro thrombogenicity test system with cyclic olefin copolymer substrate for endothelial layer formation
JF  - MRS communications / a publication of the Materials Research Society
N2  - In vitro thrombogenicity test systems require co-cultivation of endothelial cells and platelets under blood flow-like conditions. Here, a commercially available perfusion system is explored using plasma-treated cyclic olefin copolymer (COC) as a substrate for the endothelial cell layer. COC was characterized prior to endothelialization and co-cultivation with platelets under static or flow conditions. COC exhibits a low roughness and a moderate hydrophilicity. Flow promoted endothelial cell growth and prevented platelet adherence. These findings show the suitability of COC as substrate and the importance of blood flow-like conditions for the assessment of the thrombogenic risk of drugs or cardiovascular implant materials.
Y1  - 2021
U6  - https://doi.org/10.1557/s43579-021-00072-6
SN  - 2159-6867
VL  - 11
IS  - 5
SP  - 559
EP  - 567
PB  - Springer
CY  - Berlin
ER  - 
TY  - JOUR
A1  - Neusser, David
A1  - Sun, Bowen
A1  - Tan, Wen Liang
A1  - Thomsen, Lars
A1  - Schultz, Thorsten
A1  - Perdigon-Toro, Lorena
A1  - Koch, Norbert
A1  - Shoaee, Safa
A1  - McNeill, Christopher R.
A1  - Neher, Dieter
A1  - Ludwigs, Sabine
T1  - Spectroelectrochemically determined energy levels of PM6:Y6 blends and their relevance to solar cell performance
JF  - Journal of materials chemistry : C, Materials for optical and electronic devices
N2  - Recent advances in organic solar cell performance have been mainly driven forward by combining high-performance p-type donor-acceptor copolymers (e.g.PM6) and non-fullerene small molecule acceptors (e.g.Y6) as bulk-heterojunction layers. A general observation in such devices is that the device performance, e.g., the open-circuit voltage, is strongly dependent on the processing solvent. While the morphology is a typically named key parameter, the energetics of donor-acceptor blends are equally important, but less straightforward to access in the active multicomponent layer. Here, we propose to use spectral onsets during electrochemical cycling in a systematic spectroelectrochemical study of blend films to access the redox behavior and the frontier orbital energy levels of the individual compounds. Our study reveals that the highest occupied molecular orbital offset (Delta E-HOMO) in PM6:Y6 blends is similar to 0.3 eV, which is comparable to the binding energy of Y6 excitons and therefore implies a nearly zero driving force for the dissociation of Y6 excitons. Switching the PM6 orientation in the blend films from face-on to edge-on in bulk has only a minor influence on the positions of the energy levels, but shows significant differences in the open circuit voltage of the device. We explain this phenomenon by the different interfacial molecular orientations, which are known to affect the non-radiative decay rate of the charge-transfer state. We compare our results to ultraviolet photoelectron spectroscopy data, which shows distinct differences in the HOMO offsets in the PM6:Y6 blend compared to neat films. This highlights the necessity to measure the energy levels of the individual compounds in device-relevant blend films.
Y1  - 2022
U6  - https://doi.org/10.1039/d2tc01918c
SN  - 2050-7526
SN  - 2050-7534
VL  - 10
IS  - 32
SP  - 11565
EP  - 11578
PB  - Royal Society of Chemistry
CY  - Cambridge
ER  - 
TY  - JOUR
A1  - Tung, Wing Tai
A1  - Sun, Xianlei
A1  - Wang, Weiwei
A1  - Xu, Xun
A1  - Ma, Nan
A1  - Lendlein, Andreas
T1  - Structure, mechanical properties and degradation behavior of electrospun PEEU fiber meshes and films
JF  - MRS advances : a journal of the Materials Research Society (MRS)
N2  - The capability of a degradable implant to provide mechanical support depends on its degradation behavior. Hydrolytic degradation was studied for a polyesteretherurethane (PEEU70), which consists of poly(p-dioxanone) (PPDO) and poly(epsilon-caprolactone) (PCL) segments with a weight ratio of 70:30 linked by diurethane junction units. PEEU70 samples prepared in the form of meshes with average fiber diameters of 1.5 mu m (mesh1.5) and 1.2 mu m (mesh1.2), and films were sterilized and incubated in PBS at 37 degrees C with 5 vol% CO2 supply for 1 to 6 weeks. Degradation features, such as cracks or wrinkles, became apparent from week 4 for all samples. Mass loss was found to be 11 wt%, 6 wt%, and 4 wt% for mesh1.2, mesh1.5, and films at week 6. The elongation at break decreased to under 20% in two weeks for mesh1.2. In case of the other two samples, this level of degradation was achieved after 4 weeks. The weight average molecular weight of both PEEU70 mesh and film samples decreased to below 30 kg/mol when elongation at break dropped below 20%. The time period of sustained mechanical stability of PEEU70-based meshes depends on the fiber diameter and molecular weight.
Y1  - 2021
U6  - https://doi.org/10.1557/s43580-020-00001-0
SN  - 2059-8521
VL  - 6
IS  - 10
SP  - 276
EP  - 282
PB  - Springer Nature Switzerland AG
CY  - Cham
ER  - 
TY  - JOUR
A1  - Stefancu, Andrei
A1  - Nan, Lin
A1  - Zhu, Li
A1  - Chis, Vasile
A1  - Bald, Ilko
A1  - Liu, Min
A1  - Leopold, Nicolae
A1  - Maier, Stefan A.
A1  - Cortes, Emiliano
T1  - Controlling plasmonic chemistry pathways through specific ion effects
JF  - Advanced optical materials
N2  - Plasmon-driven dehalogenation of brominated purines has been recently explored as a model system to understand fundamental aspects of plasmon-assisted chemical reactions. Here, it is shown that divalent Ca2+ ions strongly bridge the adsorption of bromoadenine (Br-Ade) to Ag surfaces. 
Such ion-mediated binding increases the molecule's adsorption energy leading to an overlap of the metal energy states and the molecular states, enabling the chemical interface damping (CID) of the plasmon modes of the Ag nanostructures (i.e., direct electron transfer from the metal to Br-Ade). 
Consequently, the conversion of Br-Ade to adenine almost doubles following the addition of Ca2+. 
These experimental results, supported by theoretical calculations of the local density of states of the Ag/Br-Ade complex, indicate a change of the charge transfer pathway driving the dehalogenation reaction, from Landau damping (in the lack of Ca2+ ions) to CID (after the addition of Ca2+). 
The results show that the surface dynamics of chemical species (including water molecules) play an essential role in charge transfer at plasmonic interfaces and cannot be ignored. It is envisioned that these results will help in designing more efficient nanoreactors, harnessing the full potential of plasmon-assisted chemistry.
KW  - chemical interface damping
KW  - Hofmeister effect
KW  - hydration layer
KW  - plasmonic chemistry
KW  - specific ion effects
KW  - surface-enhanced Raman scattering
Y1  - 2022
U6  - https://doi.org/10.1002/adom.202200397
SN  - 2195-1071
VL  - 10
IS  - 14
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Banerji, Amitabh
A1  - Thyssen, Christoph
A1  - Pampel, Barbara
A1  - Huwer, Johannes
T1  - Naturwissenschaftsunterricht und Informatik
BT  - bringt zusammen, was zusammen gehört?!
BT  - bringing together, what belongs together?!
JF  - Chemie konkret : CHEMKON ; Forum für Unterricht und Didaktik
N2  - Computer literacy plays an increasingly important role in the education of 21st-century society. For chemistry' education. this results in two aspects: On the one hand. informatics education concepts can help to promote chemistry- and science-specific ways of thinking and working. On the other hand, chemistry education can contribute to information education. This paper addresses both aspects and tries to point out the Mutual benefits of informatics education and science education with regards to chemistry lessons.
N2  - Informatische Bildung spielt eine immer zentralere Rolle in der Bildung einer Gesellschaft des 21. Jahrhunderts. Für den Chemieunterricht ergeben sich daraus zwei Aspekte: Einerseits können Konzepte der informatischen Bildung dabei helfen, chemie- und naturwissenschaftsspezifische Denk- und Arbeitsweisen zu fördern. Andererseits kann der Chemieunterricht einen Beitrag für die informatische Bildung leisten. Dieser Artikel geht auf beide Aspekte ein und versucht die gegenseitigen Vorteile der informatischen Bildung und der naturwissenschaftlichen Bildung im Chemieunterricht darzustellen.
T2  - Science education and computer literacy
KW  - computer literacy
KW  - scientific literacy
KW  - informatische Bildung
KW  - naturwissenschaftliche Bildung
Y1  - 2021
U6  - https://doi.org/10.1002/ckon.202100008
SN  - 0944-5846
SN  - 1521-3730
VL  - 28
IS  - 6
SP  - 263
EP  - 265
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Zhao, Yuhang
A1  - Opitz, Andreas
A1  - Eljarrat, Alberto
A1  - Kochovski, Zdravko
A1  - Koch, Christoph
A1  - Koch, Norbert
A1  - Lu, Yan
T1  - Kinetic study on the adsorption of 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane on Ag nanoparticles in chloroform
BT  - implications for the charge transfer complex of Ag-F(4)TCNQ
JF  - ACS applied nano materials
N2  - In this study, the kinetics of the adsorption of 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F(4)TCNQ) on the surface of Ag nanoparticles (Ag NPs) in chloroform has been intensively investigated, as molecular doping is known to play a crucial role in organic electronic devices. Based on the results obtained from UV-visible (vis)-near-infrared (NIR) absorption spectroscopy, cryogenic transmission electron microscopy, scanning nanobeam electron diffraction, and electron energy loss spectroscopy, a two-step interaction kinetics has been proposed for the Ag NPs and F(4)TCNQ molecules, which includes the first step of electron transfer from Ag NPs to F(4)TCNQ indicated by the ionization of F(4)TCNQ and the second step of the formation of a Ag-F(4)TCNQ complex. The whole process has been followed via UV-vis-NIR absorption spectroscopy, which reveals distinct kinetics at two stages: the instantaneous ionization and the long-term complex formation. The kinetics and the influence of the molar ratio of Ag NPs/F(4)TCNQ molecules on the interaction between Ag NPs and F(4)TCNQ molecules in an organic solution are reported herein for the first time. Furthermore, the control experiment with silica-coated Ag NPs manifests that the charge transfer at the surface between Ag NPs and F(4)TCNQ molecules is prohibited by a silica layer of 18 nm.
KW  - Ag nanoparticles
KW  - F(4)TCNQ
KW  - phase transfer
KW  - kinetics
KW  - electron transfer
KW  - surface interaction
Y1  - 2021
U6  - https://doi.org/10.1021/acsanm.1c02153
SN  - 2574-0970
VL  - 4
IS  - 11
SP  - 11625
EP  - 11635
PB  - American Chemical Society
CY  - Washington
ER  - 
TY  - JOUR
A1  - Zhou, Shuo
A1  - Xu, Xun
A1  - Ma, Nan
A1  - Jung, Friedrich
A1  - Lendlein, Andreas
T1  - Influence of sterilization conditions on sulfate-functionalized polyGGE
JF  - Clinical hemorheology and microcirculation : blood flow and vessels
N2  - Sulfated biomolecules are known to influence numerous biological processes in all living organisms. Particularly, they contribute to prevent and inhibit the hypercoagulation condition. The failure of polymeric implants and blood contacting devices is often related to hypercoagulation and microbial contamination. Here, bioactive sulfated biomacromolecules are mimicked by sulfation of poly(glycerol glycidyl ether) (polyGGE) films. Autoclaving, gamma-ray irradiation and ethylene oxide (EtO) gas sterilization techniques were applied to functionalized materials. The sulfate group density and hydrophilicity of sulfated polymers were decreased while chain mobility and thermal degradation were enhanced post autoclaving when compared to those after EtO sterilization. These results suggest that a quality control after sterilization is mandatory to ensure the amount and functionality of functionalized groups are retained.
KW  - Sulfated polymer
KW  - sulfation
KW  - sterilization
KW  - ethylene oxide
Y1  - 2021
U6  - https://doi.org/10.3233/CH-211241
SN  - 1386-0291
SN  - 1875-8622
VL  - 79
IS  - 4
SP  - 597
EP  - 608
PB  - IOS Press
CY  - Amsterdam
ER  - 
TY  - THES
A1  - Mostafa, Amr
T1  - DNA origami nanoforks: A platform for cytochrome c single molecule surface enhanced Raman spectroscopy
N2  - This thesis presents a comprehensive exploration of the application of DNA origami nanofork antennas (DONAs) in the field of spectroscopy, with a particular focus on the structural analysis of Cytochrome C (CytC) at the single-molecule level. The research encapsulates the design, optimization, and application of DONAs in enhancing the sensitivity and specificity of Raman spectroscopy, thereby offering new insights into protein structures and interactions.
The initial phase of the study involved the meticulous optimization of DNA origami structures. This process was pivotal in developing nanoscale tools that could significantly enhance the capabilities of Raman spectroscopy. The optimized DNA origami nanoforks, in both dimer and aggregate forms, demonstrated an enhanced ability to detect and analyze molecular vibrations, contributing to a more nuanced understanding of protein dynamics.
A key aspect of this research was the comparative analysis between the dimer and aggregate forms of DONAs. This comparison revealed that while both configurations effectively identified oxidation and spin states of CytC, the aggregate form offered a broader range of detectable molecular states due to its prolonged signal emission and increased number of molecules. This extended duration of signal emission in the aggregates was attributed to the collective hotspot area, enhancing overall signal stability and sensitivity.
Furthermore, the study delved into the analysis of the Amide III band using the DONA system. Observations included a transient shift in the Amide III band's frequency, suggesting dynamic alterations in the secondary structure of CytC. These shifts, indicative of transitions between different protein structures, were crucial in understanding the protein’s functional mechanisms and interactions.
The research presented in this thesis not only contributes significantly to the field of spectroscopy but also illustrates the potential of interdisciplinary approaches in biosensing. The use of DNA origami-based systems in spectroscopy has opened new avenues for research, offering a detailed and comprehensive understanding of protein structures and interactions. The insights gained from this research are expected to have lasting implications in scientific fields ranging from drug development to the study of complex biochemical pathways. This thesis thus stands as a testament to the power of integrating nanotechnology, biochemistry, and spectroscopic techniques in addressing complex scientific questions.
N2  - Diese Dissertation präsentiert eine umfassende Untersuchung der Anwendung von DNA-Origami-Nanogabelantennen (DONAs) im Bereich der Spektroskopie, mit einem besonderen Fokus auf der strukturellen Analyse von Cytochrom C (CytC) auf Einzelmolekülebene. Die Forschung umfasst das Design, die Optimierung und die Anwendung von DONAs zur Steigerung der Sensitivität und Spezifität der Raman-Spektroskopie und bietet somit neue Einblicke in Proteinstrukturen und -interaktionen.

Die erste Phase der Studie beinhaltete die sorgfältige Optimierung von DNA-Origami-Strukturen. Dieser Prozess war entscheidend für die Entwicklung von Nanowerkzeugen, die die Fähigkeiten der Raman-Spektroskopie erheblich verbessern könnten. Die optimierten DNA-Origami-Nanogabeln, sowohl in Dimer- als auch in Aggregatform, zeigten eine verbesserte Fähigkeit, molekulare Schwingungen zu detektieren und zu analysieren, was zu einem nuancierteren Verständnis der Proteindynamik beitrug.

Ein Schlüsselaspekt dieser Forschung war die vergleichende Analyse zwischen den Dimer- und Aggregatformen von DONAs. Dieser Vergleich zeigte, dass beide Konfigurationen effektiv Oxidations- und Spin-Zustände von CytC identifizieren konnten, wobei die Aggregatform aufgrund ihrer längeren Signalemission und der erhöhten Anzahl von Molekülen ein breiteres Spektrum an detektierbaren molekularen Zuständen bot. Die verlängerte Dauer der Signalemission in den Aggregaten wurde auf den kollektiven Hotspot-Bereich zurückgeführt, der die Gesamtsignalstabilität und -empfindlichkeit erhöhte.

Darüber hinaus ging die Studie auf die Analyse der Amid-III-Bande unter Verwendung des DONA-Systems ein. Zu den Beobachtungen gehörte eine vorübergehende Verschiebung der Frequenz der Amid-III-Bande, was auf dynamische Veränderungen in der Sekundärstruktur von CytC hindeutete. Diese Verschiebungen, die auf Übergänge zwischen verschiedenen Proteinstrukturen hindeuteten, waren entscheidend für das Verständnis der funktionellen Mechanismen und Interaktionen des Proteins.

Die in dieser Dissertation präsentierte Forschung leistet nicht nur einen bedeutenden Beitrag zum Gebiet der Spektroskopie, sondern veranschaulicht auch das Potenzial interdisziplinärer Ansätze in der Biosensorik. Der Einsatz von DNA-Origami-basierten Systemen in der Spektroskopie hat neue Wege für die Forschung eröffnet und bietet ein detailliertes und umfassendes Verständnis von Proteinstrukturen und -interaktionen. Die aus dieser Forschung gewonnenen Erkenntnisse werden voraussichtlich langfristige Auswirkungen auf wissenschaftliche Bereiche haben, die von der Arzneimittelentwicklung bis hin zur Untersuchung komplexer biochemischer Prozesse reichen. Diese Dissertation steht somit als Zeugnis für die Kraft der Integration von Nanotechnologie, Biochemie und spektroskopischen Techniken bei der Beantwortung komplexer wissenschaftlicher Fragen.
KW  - DNA origami
KW  - DNA origami nanoantennas (DONA)
KW  - SERS
KW  - Cytochrome C
Y1  - 2024
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-635482
ER  - 
TY  - JOUR
A1  - Michaelis, Vivien
A1  - Aengenheister, Leonie
A1  - Tuchtenhagen, Max
A1  - Rinklebe, Jörg
A1  - Ebert, Franziska
A1  - Schwerdtle, Tanja
A1  - Buerki-Thurnherr, Tina
A1  - Bornhorst, Julia
T1  - Differences and interactions in placental manganese and iron transfer across an in vitro model of human villous trophoblasts
JF  - International journal of molecular sciences
N2  - Manganese (Mn) as well as iron (Fe) are essential trace elements (TE) important for the maintenance of physiological functions including fetal development. However, in the case of Mn, evidence suggests that excess levels of intrauterine Mn are associated with adverse pregnancy outcomes. Although Mn is known to cross the placenta, the fundamentals of Mn transfer kinetics and mechanisms are largely unknown. Moreover, exposure to combinations of TEs should be considered in mechanistic transfer studies, in particular for TEs expected to share similar transfer pathways. Here, we performed a mechanistic in vitro study on the placental transfer of Mn across a BeWo b30 trophoblast layer. Our data revealed distinct differences in the placental transfer of Mn and Fe. While placental permeability to Fe showed a clear inverse dose-dependency, Mn transfer was largely independent of the applied doses. Concurrent exposure of Mn and Fe revealed transfer interactions of Fe and Mn, indicating that they share common transfer mechanisms. In general, mRNA and protein expression of discussed transporters like DMT1, TfR, or FPN were only marginally altered in BeWo cells despite the different exposure scenarios highlighting that Mn transfer across the trophoblast layer likely involves a combination of active and passive transport processes.
KW  - manganese
KW  - iron
KW  - placental transfer
KW  - TE interactions
KW  - BeWo b30
KW  - trophoblasts
Y1  - 2022
U6  - https://doi.org/10.3390/ijms23063296
SN  - 1422-0067
VL  - 23
IS  - 6
PB  - MDPI
CY  - Basel
ER  - 
TY  - GEN
A1  - Bande, Annika
A1  - González, Leticia
A1  - Klamroth, Tillmann
A1  - Tremblay, Jean Christophe
T1  - Theoretical chemistry and quantum dynamics at interfaces
BT  - Celebrating the career of Peter Saalfrank on the occasion of his 60th birthday
T2  - Chemical physics : a journal devoted to experimental and theoretical research involving problems of both a chemical and physical nature
Y1  - 2022
U6  - https://doi.org/10.1016/j.chemphys.2022.111509
SN  - 0301-0104
SN  - 1873-4421
VL  - 558
PB  - Elsevier Science
CY  - Amsterdam [u.a.]
ER  - 
TY  - JOUR
A1  - Crovetto, Andrea
A1  - Kojda, Sandrino Danny
A1  - Yi, Feng
A1  - Heinselman, Karen N.
A1  - LaVan, David A.
A1  - Habicht, Klaus
A1  - Unold, Thomas
A1  - Zakutayev, Andriy
T1  - Crystallize It before It diffuses
BT  - kinetic stabilization of thin-film phosphorus-rich semiconductor CuP2
JF  - Journal of the american chemical society
N2  - Numerous phosphorus-rich metal phosphides containing both P-P bonds and metal-P bonds are known from the solid-state chemistry literature. A method to grow these materials in thin-film form would be desirable, as thin films are required in many applications and they are an ideal platform for high-throughput studies. In addition, the high density and smooth surfaces achievable in thin films are a significant advantage for characterization of transport and optical properties. Despite these benefits, there is hardly any published work on even the simplest binary phosphorus-rich phosphide films. Here, we demonstrate growth of single-phase CuP2 films by a two-step process involving reactive sputtering of amorphous CuP2+x and rapid annealing in an inert atmosphere. At the crystallization temperature, CuP2 is thermodynamically unstable with respect to Cu3P and P-4. However, CuP2 can be stabilized if the amorphous precursors are mixed on the atomic scale and are sufficiently close to the desired composition (neither too P poor nor too P rich). Fast formation of polycrystalline CuP2, combined with a short annealing time, makes it possible to bypass the diffusion processes responsible for decomposition. We find that thin-film CuP2 is a 1.5 eV band gap semiconductor with interesting properties, such as a high optical absorption coefficient (above 10(5) cm(-1)), low thermal conductivity (1.1 W/(K m)), and composition-insensitive electrical conductivity (around 1 S/cm). We anticipate that our processing route can be extended to other phosphorus-rich phosphides that are still awaiting thin-film synthesis and will lead to a more complete understanding of these materials and of their potential applications.
Y1  - 2022
U6  - https://doi.org/10.1021/jacs.2c04868
SN  - 0002-7863
SN  - 1520-5126
VL  - 144
IS  - 29
SP  - 13334
EP  - 13343
PB  - American Chemical Society
CY  - Washington
ER  - 
TY  - JOUR
A1  - Tung, Wing Tai
A1  - Maring, Janita A.
A1  - Xu, Xun
A1  - Liu, Yue
A1  - Becker, Matthias
A1  - Somesh, Dipthi Bachamanda
A1  - Klose, Kristin
A1  - Wang, Weiwei
A1  - Sun, Xianlei
A1  - Ullah, Imran
A1  - Kratz, Karl
A1  - Neffe, Axel T.
A1  - Stamm, Christof
A1  - Ma, Nan
A1  - Lendlein, Andreas
T1  - In vivo performance of a cell and factor free multifunctional fiber mesh modulating postinfarct myocardial remodeling
JF  - Advanced Functional Materials
N2  - Guidance of postinfarct myocardial remodeling processes by an epicardial patch system may alleviate the consequences of ischemic heart disease. As macrophages are highly relevant in balancing immune response and regenerative processes their suitable instruction would ensure therapeutic success. A polymeric mesh capable of attracting and instructing monocytes by purely physical cues and accelerating implant degradation at the cell/implant interface is designed. In a murine model for myocardial infarction the meshes are compared to those either coated with extracellular matrix or loaded with induced cardiomyocyte progenitor cells. All implants promote macrophage infiltration and polarization in the epicardium, which is verified by in vitro experiments. 6 weeks post-MI, especially the implantation of the mesh attenuates left ventricular adverse remodeling processes as shown by reduced infarct size (14.7% vs 28-32%) and increased wall thickness (854 mu m vs 400-600 mu m), enhanced angiogenesis/arteriogenesis (more than 50% increase compared to controls and other groups), and improved heart function (ejection fraction = 36.8% compared to 12.7-31.3%). Upscaling as well as process controls is comprehensively considered in the presented mesh fabrication scheme to warrant further progression from bench to bedside.
KW  - bioinstructive materials
KW  - cardiac regeneration
KW  - function by structure;
KW  - modulation of in vivo regeneration
KW  - multifunctional biomaterials
Y1  - 2022
U6  - https://doi.org/10.1002/adfm.202110179
SN  - 1616-301X
SN  - 1616-3028
VL  - 32
IS  - 31
PB  - Wiley
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Breternitz, Joachim
A1  - Schorr, Susan
T1  - Symmetry relations in wurtzite nitrides and oxide nitrides and the curious case of Pmc2(1)
JF  - Acta crystallographica / International Union of Crystallography. Section A, Foundations and advances
N2  - Binary III-V nitrides such as AlN, GaN and InN in the wurtzite-type structure have long been considered as potent semiconducting materials because of their optoelectronic properties, amongst others. With rising concerns over the utilization of scarce elements, a replacement of the trivalent cations by others in ternary and multinary nitrides has led to the development of different variants of nitrides and oxide nitrides crystallizing in lower-symmetry variants of wurtzite. This work presents the symmetry relationships between these structural types specific to nitrides and oxide nitrides and updates some prior work on this matter. The non-existence of compounds crystallizing in Pmc2(1), formally the highest subgroup of the wurtzite type fulfilling Pauling's rules for 1:1:2 stoichiometries, has been puzzling scientists for a while; a rationalization is given, from a crystallographic basis, of why this space group is unlikely to be adopted.
KW  - group-subgroup relationships
KW  - nitride materials
KW  - wurtzite type
Y1  - 2021
U6  - https://doi.org/10.1107/S2053273320015971
SN  - 2053-2733
VL  - 77
IS  - 3
SP  - 208
EP  - 216
PB  - Blackwell
CY  - Oxford [u.a.]
ER  - 
TY  - JOUR
A1  - Mei, Shilin
A1  - Siebert, Andreas
A1  - Xu, Yaolin
A1  - Quan, Ting
A1  - Garcia-Diez, Raul
A1  - Bär, Marcus
A1  - Härtel, Paul
A1  - Abendroth, Thomas
A1  - Dörfler, Susanne
A1  - Kaskel, Stefan
A1  - Lu, Yan
T1  - Large-Scale Synthesis of Nanostructured Carbon-Ti4O7 Hollow Particles as Efficient Sulfur Host Materials for Multilayer Lithium-Sulfur Pouch Cells
JF  - Batteries & supercaps
N2  - Applications of advanced cathode materials with well-designed chemical components and/or optimized nanostructures promoting the sulfur redox kinetics and suppressing the shuttle effect of polysulfides are highly valued. However, in the case of actual lithium-sulfur (Li-S) batteries under practical working conditions, one long-term obstacle still exists, which is mainly due to the difficulties in massive synthesis of such nanomaterials with low cost and ease of control on the nanostructure. Herein, we develop a facile synthesis of carbon coated Ti4O7 hollow nanoparticles (Ti4O7) using spherical polymer electrolyte brush as soft template, which is scalable via utilizing a minipilot reactor. The C Ti4O7 hollow nanoparticles provide strong chemical adsorption to polysulfides through the large polar surface and additional physical confinement by rich micro- & mesopores and have successfully been employed as an efficient sulfur host for multilayer pouch cells. Besides, the sluggish kinetics of the sulfur and lithium sulfide redox mechanism can be improved by the highly conductive Ti4O7 via catalyzation of the conversion of polysulfides. Consequently, the C-Ti4O7 based pouch cell endows a high discharge capacity of 1003 mAhg(-1) at 0.05 C, a high-capacity retention of 83.7% after 100 cycles at 0.1 C, and a high Coulombic efficiency of 97.5% at the 100th cycle. This work proposes an effective approach to transfer the synthesis of hollow Ti4O7 nanoparticles from lab- to large-scale production, paving the way to explore a wide range of advanced nanomaterials for multilayer Li-S pouch cells.
KW  - lithium-sulfur batteries
KW  - pouch cell
KW  - spherical polyelectrolyte brushes (SPB)
KW  - Ti4O7
Y1  - 2022
U6  - https://doi.org/10.1002/batt.202100398
SN  - 2566-6223
VL  - 5
IS  - 6
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Lepre, Enrico
A1  - Heske, Julian
A1  - Nowakowski, Michal
A1  - Scoppola, Ernesto
A1  - Zizak, Ivo
A1  - Heil, Tobias
A1  - Kühne, Thomas D.
A1  - Antonietti, Markus
A1  - Lopez-Salas, Nieves
A1  - Albero, Josep
T1  - Ni-based electrocatalysts for unconventional CO2 reduction reaction to formic acid
JF  - Nano energy
N2  - Electrochemical reduction stands as an alternative to revalorize CO2. Among the different alternatives, Ni single atoms supported on carbonaceous materials are an appealing catalytic solution due to the low cost and versatility of the support and the optimal usage of Ni and its predicted selectivity and efficiency (ca. 100% towards CO). Herein, we have used noble carbonaceous support derived from cytosine to load Ni subnanometric sites. The large heteroatom content of the support allows the stabilization of up to 11 wt% of Ni without the formation of nanoparticles through a simple impregnation plus calcination approach, where nickel promotes the stabilization of C3NOx frameworks and the oxidative support promotes a high oxidation state of nickel. EXAFS analysis points at nickel single atoms or subnanometric clusters coordinated by oxygen in the material surface. Unlike the wellknown N-coordinated Ni single sites selectivity towards CO2 reduction, O-coordinated-Ni single sites (ca. 7 wt% of Ni) reduced CO2 to CO, but subnanometric clusters (11 wt% of Ni) foster the unprecedented formation of HCOOH with 27% Faradaic efficiency at - 1.4 V. Larger Ni amounts ended up on the formation of NiO nanoparticles and almost 100% selectivity towards hydrogen evolution.
KW  - CO 2 reduction reaction
KW  - Noble carbon
KW  - Ni-O4 electrocatalysts
KW  - Formic acid
Y1  - 2022
U6  - https://doi.org/10.1016/j.nanoen.2022.107191
SN  - 2211-2855
SN  - 2211-3282
VL  - 97
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Haubitz, Toni
A1  - Drobot, Björn
A1  - Tsushima, Satoru
A1  - Steudtner, Robin
A1  - Stumpf, Thorsten
A1  - Kumke, Michael Uwe
T1  - Quenching mechanism of uranyl(VI) by chloride and bromide in aqueous and non-aqueous solutions
JF  - The journal of physical chemistry : A, Molecules, spectroscopy, kinetics, environment & general theory
N2  - A major hindrance in utilizing uranyl(VI) luminescence as a standard analytical tool, for example, in environmental monitoring or nuclear industries, is quenching by other ions such as halide ions, which are present in many relevant matrices of uranyl(VI) speciation. Here, we demonstrate through a combination of time-resolved laser-induced fluorescence spectroscopy, transient absorption spectroscopy, and quantum chemistry that coordinating solvent molecules play a crucial role in U(VI) halide luminescence quenching. We show that our previously suggested quenching mechanism based on an internal redox reaction of the 1:2-uranyl-halide-complex holds also true for bromide-induced quenching of uranyl(VI). By adopting specific organic solvents, we were able to suppress the separation of the oxidized halide ligand X-2(center dot-) and the formed uranyl(V) into fully solvated ions, thereby "reigniting" U(VI) luminescence. Time-dependent density functional theory calculations show that quenching occurs through the outer-sphere complex of U(VI) and halide in water, while the ligand-to-metal charge transfer is strongly reduced in acetonitrile.
Y1  - 2021
U6  - https://doi.org/10.1021/acs.jpca.1c02487
SN  - 1089-5639
SN  - 1520-5215
VL  - 125
IS  - 20
SP  - 4380
EP  - 4389
PB  - American Chemical Society
CY  - Washington
ER  - 
TY  - JOUR
A1  - Pham, Duong Tung
A1  - Quan, Ting
A1  - Mei, Shilin
A1  - Lu, Yan
T1  - Colloidal metal sulfide nanoparticles for high performance electrochemical energy storage systems
JF  - Current opinion in green and sustainable chemistry
N2  - Transition metal sulfides have emerged as excellent replacement candidates of traditional insertion electrode materials based on their conversion or alloying mechanisms, facilitating high specific capacity and rate ability. However, parasitic reactions such as massive volume change during the discharge/ charge processes, intermediate polysulfide dissolution, and passivating solid electrolyte interface formation have led to poor cyclability, hindering their feasibility and applicability in energy storage systems. Colloidal metal sulfide nanoparticles, a special class that integrates the intrinsic chemical properties of metal sulfides and their specified structural features, have fairly enlarged their contribution due to the synergistic effect. This review highlights the latest synthetic approaches based on colloidal process. Their corresponding electrochemical outcomes will also be discussed, which are thoroughly updated along with their insight scientific standpoints.
Y1  - 2022
U6  - https://doi.org/10.1016/j.cogsc.2022.100596
SN  - 2452-2236
VL  - 34
PB  - Elsevier
CY  - Amsterdam
ER  -