@article{FortesMartinThuenemannStockmannetal.2021,
  author    = {Fortes Mart{\´i}n, Rebeca and Th{\"u}nemann, Andreas F. and Stockmann, J{\"o}rg M. and Radnik, J{\"o}rg and Koetz, Joachim},
  title     = {From nanoparticle heteroclusters to filament networks by self-assembly at the water-oil interface of reverse microemulsions},
  series = {Langmuir : the ACS journal of surfaces and colloids / American Chemical Society},
  volume    = {37},
  journal   = {Langmuir : the ACS journal of surfaces and colloids / American Chemical Society},
  number    = {29},
  publisher = {American Chemical Society},
  address   = {Washington},
  issn      = {0743-7463},
  doi       = {10.1021/acs.langmuir.1c01348},
  pages     = {8876 -- 8885},
  year      = {2021},
  abstract  = {Surface self-assembly of spherical nanoparticles of sizes below 10 nm into hierarchical heterostructures is under arising development despite the inherent difficulties of obtaining complex ordering patterns on a larger scale. Due to template-mediated interactions between oil-dispersible superparamagnetic nanoparticles (MNPs) and polyethylenimine- stabilized gold nanoparticles (Au(PEI)NPs) at the water-oil interface of microemulsions, complex nanostructured films can be formed. Characterization of the reverse microemulsion phase by UV-vis absorption revealed the formation of heteroclusters from Winsor type II phases (WPII) using Aerosol-OT (AOT) as the surfactant. SAXS measurements verify the mechanism of initial nanoparticle clustering in defined dimensions. XPS suggested an influence of AOT at the MNP surface. Further, cryo-SEM and TEM visualization demonstrated the elongation of the reverse microemulsions into cylindrical, wormlike structures, which subsequently build up larger nanoparticle superstructure arrangements. Such WPII phases are thus proven to be a new form of soft template, mediating the self-assembly of different nanoparticles in hierarchical network-like filaments over a substrate during solvent evaporation.},
  language  = {en}
}
@article{GarakaniRichterBoeker2017,
  author    = {Garakani, Tayebeh Mirzaei and Richter, Marina Juliane and B{\"o}ker, Alexander},
  title     = {Controlling the bio-inspired synthesis of silica},
  series = {Journal of colloid and interface science},
  volume    = {488},
  journal   = {Journal of colloid and interface science},
  publisher = {Elsevier},
  address   = {San Diego},
  issn      = {0021-9797},
  doi       = {10.1016/j.jcis.2016.10.069},
  pages     = {322 -- 334},
  year      = {2017},
  abstract  = {The influence of different parameters on the silicification procedure using lysozyme is reported. When polyethoxysiloxane (PEOS), an internally crosslinked silica reservoir, is used, regular structures with a narrow size distribution could be obtained only via introducing the silica precursor in two steps including initial dropping and subsequent addition of residual oil phase in one portion. We found that mixing sequence of mineralizing agents in the presence of a positively charged surfactant plays a key role in terms of silica precipitation when tetraethoxyorthosilicate (TEOS) is the oil phase. In contrast, well mineralized crumpled features with high specific surface area could be synthesized in the presence of PEOS as a silica precursor polymer, regardless of mixing sequence. Moreover, introducing sodium dodecyl sulfate (SDS) as a negatively charged surfactant resulted in regular silica sphere formation only in combination with hexylene glycol (MPD) as a specific co-solvent. Finally, it is demonstrated that by inclusion of different nanoparticles even more sophisticated hybrid materials can be generated.},
  language  = {en}
}
@article{TanLiuSiemensmeyeretal.2018,
  author    = {Tan, Li and Liu, Bing and Siemensmeyer, Konrad and Glebe, Ulrich and B{\"o}ker, Alexander},
  title     = {Synthesis of thermo-responsive nanocomposites of superparamagnetic cobalt nanoparticlesipoly(N-isopropylacrylamide)},
  series = {Journal of colloid and interface science},
  volume    = {526},
  journal   = {Journal of colloid and interface science},
  publisher = {Elsevier},
  address   = {San Diego},
  issn      = {0021-9797},
  doi       = {10.1016/j.jcis.2018.04.074},
  pages     = {124 -- 134},
  year      = {2018},
  abstract  = {Novel nanocomposites of superparamagnetic cobalt nanoparticles (Co NPs) and poly(N-isopropylacrylamide) (PNIPAM) were fabricated through surface-initiated atom-transfer radical polymerization (SI-ATRP). We firstly synthesized a functional ATRP initiator, containing an amine (as anchoring group) and a 2-bromopropionate group (SI-ATRP initiator). Oleic acid- and trioctylphosphine oxide-coated Co NPs were then modified with the initiator via ligand exchange. The process is facile and rapid for efficient surface functionalization and afterwards the Co NPs can be dispersed into polar solvent DMF without aggregation. Transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and dynamic light scattering measurements confirmed the success of ligand exchange. The following polymerization of NIPAM was conducted on the surface of Co NPs. Temperature-dependent dynamic light scattering study showed the responsive behavior of PNIPAM-coated Co NPs. The combination of superparamagnetic and thermo-responsive properties in these hybrid nanoparticles is promising for future applications e.g. in biomedicine. (C) 2018 Elsevier Inc. All rights reserved.},
  language  = {en}
}
@article{FrombachUnbehauenKurniasihetal.2019,
  author    = {Frombach, Janna and Unbehauen, Michael and Kurniasih, Indah N. and Schumacher, Fabian and Volz, Pierre and Hadam, Sabrina and Rancan, Fiorenza and Blume-Peytavi, Ulrike and Kleuser, Burkhard and Haag, Rainer and Alexiev, Ulrike and Vogt, Annika},
  title     = {Core-multishell nanocarriers enhance drug penetration and reach keratinocytes and antigen-presenting cells in intact human skin},
  series = {Journal of controlled release},
  volume    = {299},
  journal   = {Journal of controlled release},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0168-3659},
  doi       = {10.1016/j.jconrel.2019.02.028},
  pages     = {138 -- 148},
  year      = {2019},
  abstract  = {In reconstructed skin and diffusion cell studies, core-multishell nanocarriers (CMS-NC) showed great potential for drug delivery across the skin barrier. Herein, we investigated penetration, release of dexamethasone (DXM), in excised full-thickness human skin with special focus on hair follicles (HF). Four hours and 16 h after topical application of clinically relevant dosages of 10 mu g DXM/cm(2) skin encapsulated in CMS-NC (12 nm diameter, 5.8\% loading), presence of DXM in the tissue as assessed by fluorescence microscopy of anti-DXM-stained tissue sections as well as ELISA and HPLC-MS/MS in tissue extracts was enhanced compared to standard LAW-creme but lower compared to DXM aqueous/alcoholic solution. Such enhanced penetration compared to conventional cremes offers high potential for topical therapies, as recurrent applications of corticosteroid solutions face limitations with regard to tolerability and fast drainage. The findings encourage more detailed investigations on where and how the nanocarrier and drug dissociate within the skin and what other factors, e.g. thermodynamic activity, influence the penetration of this formulations. Microscopic studies on the spatial distribution within the skin revealed accumulation in HF and furrows accompanied by limited cellular uptake assessed by flow cytometry (up to 9\% of total epidermal cells). FLIM clearly visualized the presence of CMS-NC in the viable epidermis and dermis. When exposed in situ a fraction of up to 25\% CD1a(+) cells were found within the epidermal CMS-NC+ population compared to approximately 3\% CD1a(+)/CMS-NC+ cells after in vitro exposure in short-term cultures of epidermal cell suspensions. The latter reflects the natural percentage of Langerhans cells (LC) in epidermis suspensions and indicated that CMS-NC were not preferentially internalized by one cell type. The increased CMS-NC+ LC proportion after exposure within the tissue is in accordance with the strategic suprabasal LC-localization. More specifically we postulate that the extensive dendrite meshwork, their position around HF orifices and their capacity to modulate tight junctions facilitated a preferential uptake of CMS-NC by LC within the skin. This newly identified aspect of CMS-NC penetration underlines the potential of CMS-NC for dermatotherapy and encourages further investigations of CMS-NC for the delivery of other molecule classes for which intracellular delivery is even more crucial.},
  language  = {en}
}
@phdthesis{Stete2020,
  author    = {Stete, Felix},
  title     = {Gold at the nanoscale},
  doi       = {10.25932/publishup-49605},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-496055},
  school      = {Universit{\"a}t Potsdam},
  pages     = {X, 186},
  year      = {2020},
  abstract  = {In this cumulative dissertation, I want to present my contributions to the field of plasmonic nanoparticle science. Plasmonic nanoparticles are characterised by resonances of the free electron gas around the spectral range of visible light. In recent years, they have evolved as promising components for light based nanocircuits, light harvesting, nanosensors, cancer therapies, and many more. This work exhibits the articles I authored or co-authored in my time as PhD student at the University of Potsdam. The main focus lies on the coupling between localised plasmons and excitons in organic dyes. Plasmon-exciton coupling brings light-matter coupling to the nanoscale. This size reduction is accompanied by strong enhancements of the light field which can, among others, be utilised to enhance the spectroscopic footprint of molecules down to single molecule detection, improve the efficiency of solar cells, or establish lasing on the nanoscale. When the coupling exceeds all decay channels, the system enters the strong coupling regime. In this case, hybrid light-matter modes emerge utilisable as optical switches, in quantum networks, or as thresholdless lasers. The present work investigates plasmon-exciton coupling in gold-dye core-shell geometries and contains both fundamental insights and technical novelties. It presents a technique which reveals the anticrossing in coupled systems without manipulating the particles themselves. The method is used to investigate the relation between coupling strength and particle size. Additionally, the work demonstrates that pure extinction measurements can be insufficient when trying to assess the coupling regime. Moreover, the fundamental quantum electrodynamic effect of vacuum induced saturation is introduced. This effect causes the vacuum fluctuations to diminish the polarisability of molecules and has not yet been considered in the plasmonic context. The work additionally discusses the reaction of gold nanoparticles to optical heating. Such knowledge is of great importance for all potential optical applications utilising plasmonic nanoparticles since optical excitation always generates heat. This heat can induce a change in the optical properties, but also mechanical changes up to melting can occur. Here, the change of spectra in coupled plasmon-exciton particles is discussed and explained with a precise model. Moreover, the work discusses the behaviour of gold nanotriangles exposed to optical heating. In a pump-probe measurement, X-ray probe pulses directly monitored the particles' breathing modes. In another experiment, the triangles were exposed to cw laser radiation with varying intensities and illumination areas. X-ray diffraction directly measured the particles' temperature. Particle melting was investigated with surface enhanced Raman spectroscopy and SEM imaging demonstrating that larger illumination areas can cause melting at lower intensities. An elaborate methodological and theoretical introduction precedes the articles. This way, also readers without specialist's knowledge get a concise and detailed overview of the theory and methods used in the articles. I introduce localised plasmons in metal nanoparticles of different shapes. For this work, the plasmons were mostly coupled to excitons in J-aggregates. Therefore, I discuss these aggregates of organic dyes with sharp and intense resonances and establish an understanding of the coupling between the two systems. For ab initio simulations of the coupled systems, models for the systems' permittivites are presented, too. Moreover, the route to the sample fabrication - the dye coating of gold nanoparticles, their subsequent deposition on substrates, and the covering with polyelectrolytes - is presented together with the measurement methods that were used for the articles.},
  language  = {en}
}
@article{BrunacciNeffeWischkeetal.2019,
  author    = {Brunacci, Nadia and Neffe, Axel T. and Wischke, Christian and Naolou, Toufik and N{\"o}chel, Ulrich and Lendlein, Andreas},
  title     = {Oligodepsipeptide (nano)carriers},
  series = {Journal of controlled release},
  volume    = {301},
  journal   = {Journal of controlled release},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0168-3659},
  doi       = {10.1016/j.jconrel.2019.03.004},
  pages     = {146 -- 156},
  year      = {2019},
  abstract  = {High drug loads of nanoparticles are essential to efficiently provide a desired dosage in the required timeframe, however, these conditions may not be reached with so far established degradable matrices. Our conceptual approach for increasing the drug load is based on strengthening the affinity between drug and matrix in combination with stabilizing drug-matrix-hybrids through strong intermolecular matrix interactions. Here, a method for designing such complex drug-matrix hybrids is introduced employing computational methods (molecular dynamics and docking) as well as experimental studies (affinity, drug loading and distribution, drug release from films and nanoparticles). As model system, dexamethasone (DXM), relevant for the treatment of inflammatory diseases, in combination with poly[(rac-lactide)-co-glycolide] (PLGA) as standard degradable matrix or oligo[(3-(S)-sec-butyl) morpholine-2,5-dione] diol (OBMD) as matrix with hypothesized stronger interaction with DXM were investigated. Docking studies predicted higher affinity of DXM to OBMD than PLGA and displayed amide bond participation in hydrogen bonding with OBMD. Experimental investigations on films and nanoparticles, i.e. matrices of different shapes and sizes, confirmed this phenomenon as shown e.g. by a similar to 10 times higher solid state solubility of DXM in OBMD than in PLGA. DXM-loaded particles of similar to 150 nm prepared by nanoprecipitation in aqueous environment had a drug loading (DL) up to 16 times higher when employing OBMD as matrix compared to PLGA carriers due to enhanced drug retention in the OBMD phase. Importantly, drug relase periods were not altered as the release from films and particles was mainly ruled by the diffusion length as well as matrix degradation rather than the matrix type, which can be assigned to water diffusing into the matrix and breaking up of drug-matrix hydrogen bonds. Overall, the presented design and fabrication scheme showed predictive power and might universally enable the screening of drug/matrix interactions particularly to expand the oligodepsipeptide platform technology, e.g. by varying the depsipeptide side chains, for drug carrier and release systems.},
  language  = {en}
}
@article{ZengFrascaRumschoetteletal.2016,
  author    = {Zeng, Ting and Frasca, Stefano and Rumsch{\"o}ttel, Jens and Koetz, Joachim and Leimk{\"u}hler, Silke and Wollenberger, Ursula},
  title     = {Role of Conductive Nanoparticles in the Direct Unmediated Bioelectrocatalysis of Immobilized Sulfite Oxidase},
  series = {Electroanalysis : an international journal devoted to fundamental and practical aspects of electroanalysis},
  volume    = {28},
  journal   = {Electroanalysis : an international journal devoted to fundamental and practical aspects of electroanalysis},
  publisher = {Wiley-VCH},
  address   = {Weinheim},
  issn      = {1040-0397},
  doi       = {10.1002/elan.201600246},
  pages     = {2303 -- 2310},
  year      = {2016},
  language  = {en}
}
@phdthesis{Abouserie2018,
  author    = {Abouserie, Ahed},
  title     = {Ionic liquid precursors for multicomponent inorganic nanomaterials},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-418950},
  school      = {Universit{\"a}t Potsdam},
  pages     = {xx, 193},
  year      = {2018},
  abstract  = {Health effects, attributed to the environmental pollution resulted from using solvents such as benzene, are relatively unexplored among petroleum workers, personal use, and laboratory researchers. Solvents can cause various health problems, such as neurotoxicity, immunotoxicity, and carcinogenicity. As such it can be absorbed via epidermal or respiratory into the human body resulting in interacting with molecules that are responsible for biochemical and physiological processes of the brain. Owing to the ever-growing demand for finding a solution, an Ionic liquid can use as an alternative solvent. Ionic liquids are salts in a liquid state at low temperature (below 100 C), or even at room temperature. Ionic liquids impart a unique architectural platform, which has been interesting because of their unusual properties that can be tuned by simple ways such as mixing two ionic liquids. Ionic liquids not only used as reaction solvents but they became a key developing for novel applications based on their thermal stability, electric conductivity with very low vapor pressure in contrast to the conventional solvents. In this study, ionic liquids were used as a solvent and reactant at the same time for the novel nanomaterials synthesis for different applications including solar cells, gas sensors, and water splitting. The field of ionic liquids continues to grow, and become one of the most important branches of science. It appears to be at a point where research and industry can work together in a new way of thinking for green chemistry and sustainable production.},
  language  = {en}
}
@article{CuiXiaMitzscherlingetal.2015,
  author    = {Cui, Qianling and Xia, Bihua and Mitzscherling, Steffen and Masic, Admir and Li, Lidong and Bargheer, Matias and Moehwald, Helmuth},
  title     = {Preparation of gold nanostars and their study in selective catalytic reactions},
  series = {Colloids and surfaces : an international journal devoted to the principles and applications of colloid and interface science ; A, Physicochemical and engineering aspects},
  volume    = {465},
  journal   = {Colloids and surfaces : an international journal devoted to the principles and applications of colloid and interface science ; A, Physicochemical and engineering aspects},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0927-7757},
  doi       = {10.1016/j.colsurfa.2014.10.028},
  pages     = {20 -- 25},
  year      = {2015},
  abstract  = {In this work, gold nanostars (AuNSs) with size around 90 nm were prepared through an easy one-step method. They show excellent catalytic activity and large surface-enhanced Raman scattering (SERS) activity at the same time. Surprisingly, they exhibited different catalytic performance on the reduction of aromatic nitro compounds with different substituents on the para position. To understand such a difference, the SERS spectra were recorded, showing that the molecular orientation of reactants on the gold surface were different. We anticipate that this research will help to understand the relationship of the molecular orientation with the catalytic activity of gold nanoparticles.},
  language  = {en}
}
@article{YarmanNagelGajovicEichelmannetal.2011,
  author    = {Yarman, Aysu and Nagel, Thomas and Gajovic-Eichelmann, Nenad and Fischer, Anna and Wollenberger, Ursula and Scheller, Frieder W.},
  title     = {Bioelectrocatalysis by Microperoxidase-11 in a Multilayer Architecture of Chitosan Embedded Gold Nanoparticles},
  series = {Electroanalysis : an international journal devoted to fundamental and practical aspects of electroanalysis},
  volume    = {23},
  journal   = {Electroanalysis : an international journal devoted to fundamental and practical aspects of electroanalysis},
  number    = {3},
  publisher = {Wiley-Blackwell},
  address   = {Malden},
  issn      = {1040-0397},
  doi       = {10.1002/elan.201000535},
  pages     = {611 -- 618},
  year      = {2011},
  abstract  = {We report on the redox behaviour of the microperoxidase-11 (MP-11) which has been electrostatically immobilized in a matrix of chitosan-embedded gold nanoparticles on the surface of a glassy carbon electrode. MP-11 contains a covalently bound heme c as the redox active group that exchanges electrons with the electrode via the gold nanoparticles. Electroactive surface concentration of MP-11 at high scan rate is between 350+/-50 pmol cm(-2), which reflects a multilayer process. The formal potential (E degrees') of MP-11 in the gold nanoparticles-chitosan film was estimated to be -(267.7+/-2.9) mV at pH 7.0. The heterogeneous electron transfer rate constant (k(s)) starts at 1.21 s(-1) and levels off at 6.45 s(-1) in the scan rate range from 0.1 to 2.0 V s(-1). Oxidation and reduction of MP-11 by hydrogen peroxide and superoxide, respectively have been coupled to the direct electron transfer of MP-11.},
  language  = {en}
}