@misc{WalkowiakLuGradzielskietal.2020, author = {Walkowiak, Jacek and Lu, Yan and Gradzielski, Michael and Zauscher, Stefan and Ballauff, Matthias}, title = {Thermodynamic analysis of the uptake of a protein in a spherical polyelectrolyte brush}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, number = {1}, issn = {1866-8372}, doi = {10.25932/publishup-51730}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-517307}, pages = {10}, year = {2020}, abstract = {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.}, language = {en} } @article{WalkowiakLuGradzielskietal.2019, author = {Walkowiak, Jacek and Lu, Yan and Gradzielski, Michael and Zauscher, Stefan and Ballauff, Matthias}, title = {Thermodynamic analysis of the uptake of a protein in a spherical polyelectrolyte brush}, series = {Macromolecular rapid communications}, volume = {41}, journal = {Macromolecular rapid communications}, number = {1}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {1022-1336}, doi = {10.1002/marc.201900421}, pages = {8}, year = {2019}, abstract = {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.}, language = {en} } @article{TebaldiCharanMavliutovaetal.2017, author = {Tebaldi, Marli Luiza and Charan, Himanshu and Mavliutova, Liliia and B{\"o}ker, Alexander and Glebe, Ulrich}, title = {Dual-Stimuli Sensitive Hybrid Materials: Ferritin-PDMAEMA by Grafting-From Polymerization}, series = {Macromolecular chemistry and physics}, volume = {218}, journal = {Macromolecular chemistry and physics}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {1022-1352}, doi = {10.1002/macp.201600529}, pages = {6}, year = {2017}, abstract = {The combination of stimuli-responsive polymers and proteins that can transport drugs is a promising approach for drug delivery. The formation of ferritin-poly(2-dimethylaminoethyl methacrylate) (PDMAEMA) conjugates by atom-transfer radical polymerization from the protein macroinitiator is described. PDMAEMA is a dual-stimuli-responsive polymer and the thermo- and pH-responsive properties of the resulting conjugates are studied in detail with dynamic light scattering (DLS). Additionally, it is demonstrated that the lower critical solution temperature (LCST) of the protein-polymer conjugates can be further adjusted by the ionic strength of the solution. The conjugates are also characterized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), matrix-assisted laser desorption ionization-time of flight (MALDI-ToF) mass spectrometry, and NMR spectroscopy. The obtained MALDI-ToF mass spectra are exceptional for protein-polymer conjugates and have not been so often reported.}, language = {en} } @misc{WessigHilleKumkeetal.2016, author = {Wessig, Pablo and Hille, Carsten and Kumke, Michael Uwe and Meiling, Till Thomas and Behrends, Nicole and Eisold, Ursula}, title = {Two-photon FRET pairs based on coumarin and DBD dyes}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-394445}, pages = {33510 -- 33513}, year = {2016}, abstract = {The synthesis and photophysical properties of two new FRET pairs based on coumarin as a donor and DBD dye as an acceptor are described. The introduction of a bromo atom dramatically increases the two-photon excitation (2PE) cross section providing a 2PE-FRET system, which is also suitable for 2PE-FLIM.}, language = {en} }