Facile Preparation of Thermoresponsive Biomaterials by Noncovalent Immobilization of Hyperbranched Polymers

Abstract

We introduce novel biomaterials prepared by the non-covalent immobilization of graft copolymers composed of hyperbranched polymers and a thermoresponsive polymer. Poly(N-isopropylacrylamide)(PNIPAM) was anchored on silica beads with hyperbranched polysiloxysilane (HBPSi) and was effective as a three-dimensional cell-cultivation material. An HBPSi graft copolymer with PNIPAM arms was drop cast onto a glass slide. The polymer-coated surface was thermoresponsive and was used in cell sheet engineering. A hyperbranched polystyrene (HBPSt) graft copolymer with PNIPAM arms was prepared and drop cast onto a polystyrene dish; this sample also showed good thermoresponsive behavior and cell sheet recovery performance. Langmuir-Blodgett film experiments reveal that the hyperbranched structures contribute to the exposure of HBPSt segments to the substrate, and are most likely responsible for enhanced copolymer immobilization.