Morphology of polystyrene-block-poly(styrene-co-acrylonitrile) and polystyrene-block-poly(styrene-co-acrylonitrile-co- 5-vinyltetrazole) diblock copolymers prepared by nitroxidemediated radical polymerization and ''click" chemistry

Well-defined polystyrene-block-poly(styrene-co-acrylonitrile) PS-block-P(S-co-AN) and poly(styrene-co-acrylonitrile-co- 5-vinyltetrazole) PS-block-P(S-co-AN-co-5VT) block copolymers with various content of acrylonitrile units in the statistical block were synthesized by nitroxide mediated radical polymerization (NMRP) and post-functionalized using efficient ''click" chemistry process. In the second step, acrylonitrile units were successfully modified using 1,3-dipolar cycloaddition (''click" chemistry) type polymer analogue reaction. The original pristine diblock copolymers can be molecularly dissolved in THF and dioxane while the ''tetrazolated" versions aggregate to clusters as determined by dynamic light scattering (DLS). Small-angle X-ray scattering (SAXS) and Transmission Electron Microscopy (TEM) revealed ordered lamellar morphology with interlamellar spacing d = 60 nm increasing to d = 80 nm for ''tetrazolated" diblock copolymers. The morphological features of diblock copolymer thin layers observed by Atomic Force Microscopy (AFM) depend on the tunable content of both acrylonitrile and 5-vinyltetrazole units and on the quality (polarity) of the solvents used

Self-Assembly of Well Defined PS-b-PDMS Copolymers in Bulk and in Selective Solvent

The synthesis of poly(styrene)-block-poly(dimethylsiloxane) (PS-b-PDMS) copolymers through sequential anionic polymerization, and their self-assembly behavior in bulk (thin films) and in solution (nanoparticles) is herein reported. The results obtained in bulk showed the formation of original island-type nanostructures with periodic separation and uniform height for thin films prepared by spin coating on silicon substrates followed by thermo- or solvent annealing, as evidenced by atomic force microscopy (AFM). In selective solvent (dimethylformamide), micellar core (PDMS) - shell (PS) nanoparticles originated upon direct dissolution, and the corresponding structure was determined in details by combining static and dynamic light scattering (SDLS) measurements.Fil: Ninago, Mario Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; ArgentinaFil: Ciolino, Andrés Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; ArgentinaFil: Villar, Marcelo Armando. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; ArgentinaFil: Giacomelli, Fernando C.. Insitute of Macromolecular Chemistry; República ChecaFil: Cernoch, Petr. Insitute of Macromolecular Chemistry; República ChecaFil: Stepánek, Petr. Insitute of Macromolecular Chemistry; República ChecaFil: Schmidt, Vanesa. Universidade de Caxias do Sul; BrasilFil: Giacomelli, Cristiano. Centro de Ciências Exatas E Tecnologia; Brasi

Koloidálně stabilní polypeptidové nanogely: Studie enzymem-zprostředkované nanogelace v inverzní miniemulzi

The current work presents a pivotal study of the nanogelation of the linear poly(N-5-2-hydroxypropyl-L-glutamine) polymer precursor containing tyramine (TYR) units in an inverse miniemulsion by horseradish peroxidase/H2O2-mediated crosslinking. The effects of various n(H2O2)/n(TYR) ratios on the kinetics of nanogelation in the inverse miniemulsion and on the reaction time are investigated by linear sweep voltammetry, while the formation of dityramine crosslinking is explored by fluorescence spectroscopy. The study is completed using dynamic light scattering measurements, nanoparticle tracking analysis, and cryogenic transmission electron microscopy to acquire comprehensive information about the formed nanoparticulate systems. With the optimal ratio n(H2O2)/n(TYR) = 2, the strategy yields in the high-quality 130 nm poly(amino acid)-based nanogel, which is prepared in 2 h. The nanogel is colloidally stable under different temperature and pH conditions for over 168 h. Moreover, the demonstrated nanogel is noncytotoxic for HeLa cells and human primary fibroblasts and is quickly enzymatically hydrolyzed into small fragments during a biodegradation study in human blood plasma. (c) 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 137, 48725.Tato práce představuje klíčovou studii nanogelace lineárního poly (N-5-2-hydroxypropyl-L-glutamin) polymerního prekurzoru obsahujícího jednotky tyraminu (TYR) v inverzní miniemulzi zesíťováním zprostředkovaným křenovou peroxidázou / H2O2. Účinky různých poměrů n (H2O2) / n (TYR) na kinetiku nanogelace v inverzní miniemulzi a na reakční dobu se zkoumají pomocí lineární rozmítané voltametrie, zatímco tvorba zesítění dityraminu se zkoumá fluorescenční spektroskopií. Studie je dokončena pomocí dynamických měření rozptylu světla, analýzy sledování nanočástic a kryogenní transmisní elektronové mikroskopie za účelem získání komplexních informací o vytvořených nanočásticových systémech. Při optimálním poměru n (H2O2) / n (TYR) = 2 dává strategie vysoce kvalitní nanogel na bázi 130 nm poly (aminokyseliny), který je připraven za 2 hodiny. Nanogel je koloidně stabilní za různých podmínek teploty a pH po více než 168 hodin. Kromě toho je prokázaný nanogel necytotoxický pro HeLa buňky a lidské primární fibroblasty a je rychle enzymaticky hydrolyzován na malé fragmenty během biodegradační studie v lidské krevní plazmě

Thermoresponsive properties of polyacrylamides in physiological solutions

Polymer solutions with a lower critical solution temperature (LCST) undergo reversible phase separation when heated above their cloud point temperature (T-CP or CPT). As such, they have been proposed for a wide range of biomedical applications, from injectable drug depots to switchable coatings for cell adhesion. However, in systematic studies, the T-CP of these thermoresponsive polymers has been mostly measured in non-physiological solutions, thereby hindering the development of their medicinal applications. Here, we analysed the thermoresponsive properties of four acrylamide-based polymers with LCST, namely poly[(N-2,2-difluoroethyl)acrylamide] (pDFEA), poly[(N-isopropyl)acrylamide] (pNIPAM), poly[(N,N-diethyl)acrylamide] (pDEA), and poly[(N-acryloyl)pyrrolidine] (pAP). As shown by turbidimetty, their T-CP in phosphate saline buffer (PBS) and foetal bovine serum (FBS) were consistently lower than those reported in the literature, typically assessed in pure water, even when using the same setup. in addition, these physiological solutions affected the variation of T-CP as a function of polymer concentration (1.25 to 10.0 mg mL(-)(1)) and molar mass (20 to 50 kg mol(-1)). As shown by isothermal calorimetry, interactions between proteins in FBS and polymer aggregates were predominantly exothermic, which indicates that protein polymer complexes are formed through enthalpically driven processes. in conclusion, the T-CP of thermoresponsive polymers strongly depends on solvent composition and therefore should be measured under physiological conditions for future medicinal applications