title: Structure and Rheology of Poloxamine T1107 and Its Nanocomposite Hydrogels with Cyclodextrin-Modified Barium Titanate Nanoparticles.
abstract: We report the preparation of a nanocomposite hydrogel based on a poloxamine gel matrix (Tetronic T1107) and cyclodextrin (CD)-modified barium titanate (BT) nanoparticles. The micellization and sol-gel behavior of pH-responsive block copolymer T1107 were fully characterized by small-angle neutron scattering (SANS), dynamic light scattering (DLS), and Fourier transform infrared attenuated total reflectance (FTIR-ATR) spectroscopy as a function of concentration, pH and temperature. SANS results reveal that spherical micelles in the low concentration regime present a dehydrated core and highly hydrated shell, with a small aggregation number and size, highly dependent on the degree of protonation of the central amine spacer. At high concentration, T1107 undergoes a sol-gel transition, which is inhibited at acidic pH. Nanocomposites were prepared by incorporating CD-modified BT of two different sizes (50 and 200 nm) in concentrated polymer solutions. Rheological measurements show a broadening of the gel region, as well as an improvement of the mechanical properties, as assessed by the shear elastic modulus, G' (up to 200% increase). Initial cytocompatibility studies of the nanocomposites show that the materials are nontoxic with viabilities over 70% for NIH3T3 fibroblast cell lines. Overall, the combination of Tetronics and modified BaTiO3 provides easily customizable systems with promising applications as soft piezoelectric materials.
authors.affiliation: Departamento de Química, Universidad de Navarra , 31080 Pamplona, Spain.
authors.forename: Rafael
authors.initials: R
authors.lastname: Serra-Gómez
authors.affiliation: Institute of Pharmaceutical Science, King's College London , Franklin-Wilkins Building, 150 Stamford Street, London SE1 9NH, United Kingdom.
authors.forename: Cécile A
authors.initials: CA
authors.lastname: Dreiss
authors.affiliation: Department of Materials Science and Engineering, IQMAAB, Universidad Carlos III de Madrid , 28911 Leganés, Spain.
authors.forename: Javier
authors.initials: J
authors.lastname: González-Benito
authors.affiliation: Departamento de Química, Universidad de Navarra , 31080 Pamplona, Spain.
authors.forename: Gustavo
authors.initials: G
authors.lastname: González-Gaitano