TY - JOUR A1 - Nizardo, Noverra M. A1 - Schanzenbach, Dirk A1 - Schönemann, Eric A1 - Laschewsky, Andre T1 - Exploring poly(ethylene glycol)-polyzwitterion diblock copolymers as biocompatible smart macrosurfactants featuring UCST-phase behavior in normal saline solution JF - Polymers N2 - Nonionic-zwitterionic diblock copolymers are designed to feature a coil-to-globule collapse transition with an upper critical solution temperature (UCST) in aqueous media, including physiological saline solution. The block copolymers that combine presumably highly biocompatible blocks are synthesized by chain extension of a poly(ethylene glycol) (PEG) macroinitiator via atom transfer radical polymerization (ATRP) of sulfobetaine and sulfabetaine methacrylates. Their thermoresponsive behavior is studied by variable temperature turbidimetry and H-1 NMR spectroscopy. While the polymers with polysulfobetaine blocks exhibit phase transitions in the physiologically interesting window of 30-50 degrees C only in pure aqueous solution, the polymers bearing polysulfabetaine blocks enabled phase transitions only in physiological saline solution. By copolymerizing a pair of structurally closely related sulfo-and sulfabetaine monomers, thermoresponsive behavior can be implemented in aqueous solutions of both low and high salinity. Surprisingly, the presence of the PEG blocks can affect the UCST-transitions of the polyzwitterions notably. In specific cases, this results in "schizophrenic" thermoresponsive behavior displaying simultaneously an UCST and an LCST (lower critical solution temperature) transition. Exploratory experiments on the UCST-transition triggered the encapsulation and release of various solvatochromic fluorescent dyes as model "cargos" failed, apparently due to the poor affinity even of charged organic compounds to the collapsed state of the polyzwitterions. KW - block copolymer KW - amphiphile KW - macrosurfactant KW - thermoresponsive self-assembly KW - polyzwitterion KW - upper critical solution temperature (UCST) KW - salting-in Y1 - 2018 U6 - https://doi.org/10.3390/polym10030325 SN - 2073-4360 VL - 10 IS - 3 PB - MDPI CY - Basel ER - TY - JOUR A1 - Taubert, Andreas A1 - Balischewski, Christian A1 - Hentrich, Doreen A1 - Elschner, Thomas A1 - Eidner, Sascha A1 - Günter, Christina A1 - Behrens, Karsten A1 - Heinze, Thomas T1 - Water-Soluble Cellulose Derivatives Are Sustainable Additives for Biomimetic Calcium Phosphate Mineralization JF - Inorganics : open access journal N2 - The effect of cellulose-based polyelectrolytes on biomimetic calcium phosphate mineralization is described. Three cellulose derivatives, a polyanion, a polycation, and a polyzwitterion were used as additives. Scanning electron microscopy, X-ray diffraction, IR and Raman spectroscopy show that, depending on the composition of the starting solution, hydroxyapatite or brushite precipitates form. Infrared and Raman spectroscopy also show that significant amounts of nitrate ions are incorporated in the precipitates. Energy dispersive X-ray spectroscopy shows that the Ca/P ratio varies throughout the samples and resembles that of other bioinspired calcium phosphate hybrid materials. Elemental analysis shows that the carbon (i.e., polymer) contents reach 10% in some samples, clearly illustrating the formation of a true hybrid material. Overall, the data indicate that a higher polymer concentration in the reaction mixture favors the formation of polymer-enriched materials, while lower polymer concentrations or high precursor concentrations favor the formation of products that are closely related to the control samples precipitated in the absence of polymer. The results thus highlight the potential of (water-soluble) cellulose derivatives for the synthesis and design of bioinspired and bio-based hybrid materials. KW - cellulose KW - polyamine KW - polyammonium salt KW - polycarboxylate KW - polyzwitterion KW - calcium phosphate KW - biomineralization KW - brushite KW - hydroyxapatite KW - biomaterial Y1 - 2016 U6 - https://doi.org/10.3390/inorganics4040033 SN - 2304-6740 VL - 4 PB - MDPI CY - Basel ER - TY - JOUR A1 - Hildebrand, Viet A1 - Laschewsky, André A1 - Zehm, Daniel T1 - On the hydrophilicity of polyzwitterion poly (N, N-dimethyl-N(3-(methacrylamido)propyl)ammoniopropane sulfonate) in water, deuterated water, and aqueous salt solutions JF - Journal of biomaterials science : Polymer edition KW - polyzwitterion KW - sulfobetaine KW - synthesis KW - fluorescence label KW - upper critical solution temperature KW - isotope effect KW - anti-polyelectrolyte effect Y1 - 2014 U6 - https://doi.org/10.1080/09205063.2014.939918 SN - 0920-5063 SN - 1568-5624 VL - 25 IS - 14-15 SP - 1602 EP - 1618 PB - Routledge, Taylor & Francis Group CY - Abingdon ER - TY - JOUR A1 - Laschewsky, André T1 - Structures and synthesis of zwitterionic polymers JF - Polymers N2 - The structures and synthesis of polyzwitterions ("polybetaines") are reviewed, emphasizing the literature of the past decade. Particular attention is given to the general challenges faced, and to successful strategies to obtain polymers with a true balance of permanent cationic and anionic groups, thus resulting in an overall zero charge. Also, the progress due to applying new methodologies from general polymer synthesis, such as controlled polymerization methods or the use of "click" chemical reactions is presented. Furthermore, the emerging topic of responsive ("smart") polyzwitterions is addressed. The considerations and critical discussions are illustrated by typical examples. KW - review KW - polyzwitterion KW - polyampholyte KW - zwitterionic group KW - betaine KW - synthesis KW - monomer KW - polymerization KW - post-polymerization modification Y1 - 2014 U6 - https://doi.org/10.3390/polym6051544 SN - 2073-4360 VL - 6 IS - 5 SP - 1544 EP - 1601 PB - MDPI CY - Basel ER -