Preparation of hyperbranched polystyrene-g-poly(N-isopropylacrylamide) copolymers and its application to novel thermo-responsive cell culture dishes

This paper describes the preparation of hyperbranched polystyrene-g-poly(N-isopropylacrylamide) (HBPSt-g-PNIPAM) and its application as a novel thermo-responsive material for cell sheet preparation. HBPSt-g-PNIPAM was synthesized by grafting PNIPAM from the termini of HBPSt via reversible addition fragmentation transfer polymerization. The resulting HBPSt-g-PNIPAM was cast from a solution onto a commercial polystyrene-based dish (PS-dish) to make a thermo-responsive surface for cell cultivation (P4/PS-dish). Mouse 3T3 fibroblast cells were seeded on the P4/PS-dish with 2.5-3.5 mu g/cm(2) of PNIPAM and cultured at 37 degrees C for four days to achieve high confluency. Fairly large cell sheets were successfully collected by cooling the dish to 20 degrees C. The current material avoids the use of electron beam polymerization, which requires complicated equipment, for fabricating a thermo-responsive surface because PNIPAM is immobilized by the affinity between the hyperbranched polystyrene segment and the PS-dish. (C) 2015 Elsevier Ltd. All rights reserved.