TY - JOUR A1 - Yang, Guang A1 - Zheng, Wei A1 - Tao, Guoqing A1 - Wu, Libin A1 - Zhou, Qi-Feng A1 - Kochovski, Zdravko A1 - Ji, Tan A1 - Chen, Huaijun A1 - Li, Xiaopeng A1 - Lu, Yan A1 - Ding, Hong-ming A1 - Yang, Hai-Bo A1 - Chen, Guosong A1 - Jiang, Ming T1 - Diversiform and Transformable Glyco-Nanostructures Constructed from Amphiphilic Supramolecular Metallocarbohydrates through Hierarchical Self-Assembly: The Balance between Metallacycles and Saccharides JF - ACS nano N2 - During the past decade, self-assembly of saccharide-containing amphiphilic molecules toward bioinspired functional glycomaterials has attracted continuous attention due to their various applications in fundamental and practical areas. However, it still remains a great challenge to prepare hierarchical glycoassemblies with controllable and diversiform structures because of the complexity of saccharide structures and carbohydrate-carbohydrate interactions. Herein, through hierarchical self-assembly of modulated amphiphilic supramolecular metallocarbohydrates, we successfully prepared various well-defined glyco-nanostructures in aqueous solution, including vesicles, solid spheres, and opened vesicles depending on the molecular structures of metallocarbohydrates. More attractively, these glyco-nanostructures can further transform into other morphological structures in aqueous solutions such as worm-like micelles, tubules, and even tupanvirus-like vesicles (TVVs). It is worth mentioning that distinctive anisotropic structures including the opened vesicles (OVs) and TVVs were rarely reported in glycobased nano-objects. This intriguing diversity was mainly controlled by the subtle structural trade-off of the two major components of the amphiphiles, i.e., the saccharides and metallacycles. To further understand this precise structural control, molecular simulations provided deep physical insights on the morphology evolution and balancing of the contributions from saccharides and metallacycles. Moreover, the multivalency of glyco-nanostructures with different shapes and sizes was demonstrated by agglutination with a diversity of sugarbinding protein receptors such as the plant lectins Concanavalin A (ConA). This modular synthesis strategy provides access to systematic tuning of molecular structure and self-assembled architecture, which undoubtedly will broaden our horizons on the controllable fabrication of biomimetic glycomaterials such as biological membranes and supramolecular lectin inhibitors. KW - glycomaterials KW - diversiform structures KW - hierarchical self-assembly KW - metallocarbohydrates KW - anisotropic structures Y1 - 2019 U6 - https://doi.org/10.1021/acsnano.9b07134 SN - 1936-0851 SN - 1936-086X VL - 13 IS - 11 SP - 13474 EP - 13485 PB - American Chemical Society CY - Washington ER - TY - JOUR A1 - Rothe, Martin A1 - Zhao, Yuhang A1 - Kewes, Günter A1 - Kochovski, Zdravko A1 - Sigle, Wilfried A1 - van Aken, Peter A. A1 - Koch, Christoph A1 - Ballauff, Matthias A1 - Lu, Yan A1 - Benson, Oliver T1 - Silver nanowires with optimized silica coating as versatile plasmonic resonators JF - Scientific reports N2 - Metal nanoparticles are the most frequently used nanostructures in plasmonics. However, besides nanoparticles, metal nanowires feature several advantages for applications. Their elongation offers a larger interaction volume, their resonances can reach higher quality factors, and their mode structure provides better coupling into integrated hybrid dielectric-plasmonic circuits. It is crucial though, to control the distance of the wire to a supporting substrate, to another metal layer or to active materials with sub-nanometer precision. A dielectric coating can be utilized for distance control, but it must not degrade the plasmonic properties. In this paper, we introduce a controlled synthesis and coating approach for silver nanowires to fulfill these demands. We synthesize and characterize silver nanowires of around 70 nm in diameter. These nanowires are coated with nm-sized silica shells using a modified Stober method to achieve a homogeneous and smooth surface quality. We use transmission electron microscopy, dark-field microscopy and electron-energy loss spectroscopy to study morphology and plasmonic resonances of individual nanowires and quantify the influence of the silica coating. Thorough numerical simulations support the experimental findings showing that the coating does not deteriorate the plasmonic properties and thus introduce silver nanowires as usable building blocks for integrated hybrid plasmonic systems. Y1 - 2019 U6 - https://doi.org/10.1038/s41598-019-40380-5 SN - 2045-2322 VL - 9 PB - Nature Publ. Group CY - London ER - TY - JOUR A1 - Al Nakeeb, Noah A1 - Kochovski, Zdravko A1 - Li, Tingting A1 - Zhang, Youjia A1 - Lu, Yan A1 - Schmidt, Bernhard V. K. J. T1 - Poly(ethylene glycol) brush-b-poly(N-vinylpyrrolidone)-based double hydrophilic block copolymer particles crosslinked via crystalline alpha-cyclodextrin domains JF - RSC Advances N2 - Self-assembly of block copolymers is a significant area of polymer science. The self-assembly of completely water-soluble block copolymers is of particular interest, albeit a challenging task. In the present work the self-assembly of a linear-brush architecture block copolymer, namely poly(N-vinylpyrrolidone)-b-poly(oligoethylene glycol methacrylate) (PVP-b-POEGMA), in water is studied. Moreover, the assembled structures are crosslinked via alpha-CD host/guest complexation in a supramolecular way. The crosslinking shifts the equilibrium toward aggregate formation without switching off the dynamic equilibrium of double hydrophilic block copolymer (DHBC). As a consequence, the self-assembly efficiency is improved without extinguishing the unique DHBC self-assembly behavior. In addition, decrosslinking could be induced without a change in concentration by adding a competing complexation agent for alpha-CD. The self-assembly behavior was followed by DLS measurement, while the presence of the particles could be observed via cryo-TEM before and after crosslinking. Y1 - 2019 U6 - https://doi.org/10.1039/c8ra10672j SN - 2046-2069 VL - 9 IS - 9 SP - 4993 EP - 5001 PB - Royal Society of Chemistry CY - Cambridge ER - TY - JOUR A1 - Khodeir, Miriam A1 - Ernould, Bruno A1 - Brassinne, Jeremy A1 - Ghiassinejad, Sina A1 - Jia, He A1 - Antoun, Sayed A1 - Friebe, Christian A1 - Schubert, Ulrich S. A1 - Kochovski, Zdravko A1 - Lu, Yan A1 - Van Ruymbeke, Evelyne A1 - Gohy, Jean-Francois T1 - Synthesis and characterisation of redox hydrogels based on stable nitroxide radicals JF - Soft matter N2 - The principle of encapsulation/release of a guest molecule from stimuli responsive hydrogels (SRHs) is mainly realised with pH, temperature or light stimuli. However, only a limited number of redox responsive hydrogels have been investigated so far. We report here the development of a SRH that can release its guest molecule upon a redox stimulus. To obtain this redox hydrogel, we have introduced into the hydrogel the 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO) stable nitroxide radical, which can be reversibly oxidized into an oxoammonium cation (TEMPO+). Water solubility is provided by the presence of the (oligoethyleneglycol)methacrylate (OEGMA) comonomer. Electrochemical and mechanical characterization showed that those gels exhibit interesting physicochemical properties, making them very promising candidates for practical use in a wide range of applications. Y1 - 2019 U6 - https://doi.org/10.1039/c9sm00905a SN - 1744-683X SN - 1744-6848 VL - 15 IS - 31 SP - 6418 EP - 6426 PB - Royal Society of Chemistry CY - Cambridge ER - TY - JOUR A1 - Zhang, Su-Yun A1 - Kochovski, Zdravko A1 - Lee, Hui-Chun A1 - Lu, Yan A1 - Zhang, Hemin A1 - Zhang, Jie A1 - Sun, Jian-Ke A1 - Yuan, Jiayin T1 - Ionic organic cage-encapsulating phase-transferable metal clusters JF - Chemical science N2 - Exploration of metal clusters (MCs) adaptive to both aqueous and oil phases without disturbing their size is promising for a broad scope of applications. The state-of-the-art approach via ligand-binding may perturb MCs' size due to varied metal–ligand binding strength when shuttling between solvents of different polarity. Herein, we applied physical confinement of a series of small noble MCs (<1 nm) inside ionic organic cages (I-Cages), which by means of anion exchange enables reversible transfer of MCs between aqueous and hydrophobic solutions without varying their ultrasmall size. Moreover, the MCs@I-Cage hybrid serves as a recyclable, reaction-switchable catalyst featuring high activity in liquid-phase NH3BH3 (AB) hydrolysis reaction with a turnover frequency (TOF) of 115 min−1. Y1 - 2019 U6 - https://doi.org/10.1039/c8sc04375b SN - 2041-6520 SN - 2041-6539 VL - 10 IS - 5 SP - 1450 EP - 1456 PB - Royal Society of Chemistry CY - Cambridge ER - TY - JOUR A1 - Walkowiak, Jacek A1 - Lu, Yan A1 - Gradzielski, Michael A1 - Zauscher, Stefan A1 - Ballauff, Matthias T1 - Thermodynamic analysis of the uptake of a protein in a spherical polyelectrolyte brush JF - Macromolecular rapid communications N2 - A thermodynamic study of the adsorption of Human Serum Albumin (HSA) onto spherical polyelectrolyte brushes (SPBs) by isothermal titration calorimetry (ITC) is presented. The SPBs are composed of a solid polystyrene core bearing long chains of poly(acrylic acid). ITC measurements done at different temperatures and ionic strengths lead to a full set of thermodynamicbinding constants together with the enthalpies and entropies of binding. The adsorption of HSA onto SPBs is described with a two-step model. The free energy of binding Delta Gb depends only weakly on temperature because of a marked compensation of enthalpy by entropy. Studies of the adsorbed HSA by Fourier transform infrared spectroscopy (FT-IR) demonstrate no significant disturbance in the secondary structure of the protein. The quantitative analysis demonstrates that counterion release is the major driving force for adsorption in a process where proteins become multivalent counterions of the polyelectrolyte chains upon adsorption. A comparison with the analysis of other sets of data related to the binding of HSA to polyelectrolytes demonstrates that the cancellation of enthalpy and entropy is a general phenomenon that always accompanies the binding of proteins to polyelectrolytes dominated by counterion release. KW - Spherical polyelectrolyte brushes KW - proteins KW - ITC KW - thermodynamics KW - enthalpy-entropy compensation (EEC) Y1 - 2019 U6 - https://doi.org/10.1002/marc.201900421 SN - 1022-1336 SN - 1521-3927 VL - 41 IS - 1 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Gu, Sasa A1 - Risse, Sebastian A1 - Lu, Yan A1 - Ballauff, Matthias T1 - Mechanism of the oxidation of 3,3′,5,5′-tetramethylbenzidine catalyzed by peroxidase-like Pt nanoparticles immobilized in spherical polyelectrolyte brushes BT - a kinetic study JF - ChemPhysChem N2 - Experimental and kinetic modelling studies are presented to investigate the mechanism of 3,3 ',5,5 '-tetramethylbenzidine (TMB) oxidation by hydrogen peroxide (H2O2) catalyzed by peroxidase-like Pt nanoparticles immobilized in spherical polyelectrolyte brushes (SPB-Pt). Due to the high stability of SPB-Pt colloidal, this reaction can be monitored precisely in situ by UV/VIS spectroscopy. The time-dependent concentration of the blue-colored oxidation product of TMB expressed by different kinetic models was used to simulate the experimental data by a genetic fitting algorithm. After falsifying the models with abundant experimental data, it is found that both H2O2 and TMB adsorb on the surface of Pt nanoparticles to react, indicating that the reaction follows the Langmuir-Hinshelwood mechanism. A true rate constant k, characterizing the rate-determining step of the reaction and which is independent on the amount of catalysts used, is obtained for the first time. Furthermore, it is found that the product adsorbes strongly on the surface of nanoparticles, thus inhibiting the reaction. The entire analysis provides a new perspective to study the catalytic mechanism and evaluate the catalytic activity of the peroxidase-like nanoparticles. KW - kinetics KW - nanoparticles KW - reaction mechanisms KW - spherical polyelectrolyte KW - brushes KW - UV KW - vis spectroscopy Y1 - 2019 U6 - https://doi.org/10.1002/cphc.201901087 SN - 1439-4235 SN - 1439-7641 VL - 21 IS - 5 SP - 450 EP - 458 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Jia, He A1 - Quan, Ting A1 - Liu, Xuelian A1 - Bai, Lu A1 - Wang, Jiande A1 - Boujioui, Fadoi A1 - Ye, Ran A1 - Vald, Alexandru A1 - Lu, Yan A1 - Gohy, Jean-Francois T1 - Core-shell nanostructured organic redox polymer cathodes with superior performance JF - Nano Energy N2 - Core-shell nanoparticles stabilized by a cationic surfactant are prepared from the poly(2,2,6,6-tetra-methylpiperidinyloxy-4-yl methacrylate) redox polymer. The nanoparticles are further self-assembled with negatively charged reduced graphene oxide nanosheets and negatively charged mull-walled carbon nanotubes. This results in the formation of a free-standing cathode with a layered nanostructure and a high content of redox polymer that exhibits 100% utilization of the active substance with a measured capacity as high as 105 mAh/g based on the whole weight of the electrode. KW - Nanostructured KW - Redox polymer KW - Organic electrode KW - Lithium ion battery KW - Energy storage Y1 - 2019 U6 - https://doi.org/10.1016/j.nanoen.2019.103949 SN - 2211-2855 SN - 2211-3282 VL - 64 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Quan, Ting A1 - Goubard-Bretesche, Nicolas A1 - Haerk, Eneli A1 - Kochovski, Zdravko A1 - Mei, Shilin A1 - Pinna, Nicola A1 - Ballauff, Matthias A1 - Lu, Yan T1 - Highly Dispersible Hexagonal Carbon-MoS2-Carbon Nanoplates with Hollow Sandwich Structures for Supercapacitors JF - Chemistry - a European journal N2 - MoS2, a typical layered transition-metal dichalcogenide, is promising as an electrode material in supercapacitors. However, its low electrical conductivity could lead to limited capacitance if applied in electrochemical devices. Herein, a new nanostructure composed of hollow carbon-MoS2-carbon was successfully synthesized through an L-cysteine-assisted hydrothermal method by using gibbsite as a template and polydopamine as a carbon precursor. After calcination and etching of the gibbsite template, uniform hollow platelets, which were made of a sandwich-like assembly of partial graphitic carbon and two-dimensional layered MoS2 flakes, were obtained. The platelets showed excellent dispersibility and stability in water, and good electrical conductivity due to carbon provided by the calcination of polydopamine coatings. The hollow nanoplate morphology of the material provided a high specific surface area of 543 m(2) g(-1), a total pore volume of 0.677 cm(3) g(-1), and fairly small mesopores (approximate to 5.3 nm). The material was applied in a symmetric supercapacitor and exhibited a specific capacitance of 248 F g(-1) (0.12 F cm(-2)) at a constant current density of 0.1 Ag-1; thus suggesting that hollow carbon-MoS2 carbon nanoplates are promising candidate materials for supercapacitors. KW - carbon KW - chalcogens KW - electrochemistry KW - nanostructures KW - supercapacitors Y1 - 2019 U6 - https://doi.org/10.1002/chem.201806060 SN - 0947-6539 SN - 1521-3765 VL - 25 IS - 18 SP - 4757 EP - 4766 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Jia, He A1 - Friebe, Christian A1 - Schubert, Ulrich S. A1 - Zhang, Xiaozhe A1 - Quan, Ting A1 - Lu, Yan A1 - Gohy, Jean-Francois T1 - Core-Shell Nanoparticles with a Redox Polymer Core and a Silica Porous Shell as High-Performance Cathode Material for Lithium-Ion Batteries JF - Energy technology : generation, conversion, storage, distribution N2 - A facile and novel method for the fabrication of core-shell nanoparticles (PTMA@SiO2) based on a poly(2,2,6,6-tetramethylpiperidinyloxy-4-yl methacrylate) (PTMA) core and a porous SiO2 shell is reported. The core-shell nanoparticles are further self-assembled with negatively charged multi-walled carbon nanotubes (MWCNTs), which results in the formation of a free-standing cathode electrode. The porous SiO2 shell not only effectively improves the stability of the linear PTMA redox polymer with low molar mass in organic electrolytes but also leads to the uniform dispersion of PTMA active units in the MWCNTs conductive network. The PTMA@SiO2@MWCNT composite electrode exhibits a specific capacity as high as 73.8 mAh g at 1 C and only 0.11% capacity loss per cycle at a rate of 2 C. KW - composite electrodes KW - core-shell nanoparticles KW - energy storage KW - lithium-ion batteries KW - redox polymers Y1 - 2019 U6 - https://doi.org/10.1002/ente.201901040 SN - 2194-4288 SN - 2194-4296 VL - 8 IS - 3 PB - Wiley-VCH CY - Weinheim ER -