Thermoresponsive block-copolymer brush-modified interfaces for effective fabrication of hepatocyte sheets

Abstract

Hepatic tissue engineering has been investigated for the treatment of liver disease. One promising tissue is the hepatocyte sheet, cultured in temperature-responsive cell culture dishes. However, the preparation of hepatocyte sheets requires precoating of the dish with fetal bovine serum (FBS), which is not desirable for clinical applications. To overcome this issue, we developed a thermoresponsive polymer-modified glass with an affinity for hepatocytes. Poly(N-p-vinylbenzyl-O-β-d-galactopyranosyl-(1→4)-d-guliconamide)-b-poly(N-isopropylacrylamide) (PVLA-b-PNIPAAm) was prepared through two steps of atom transfer radical polymerization (ATRP). The prepared copolymer brushes were characterized using X-ray photoelectron spectroscopy, atomic force microscopy, gel permeation chromatography, contact angle measurements, and fluorescence labeled-fibronectin and -lectin adsorption assays. These characterizations showed that the smooth block copolymer layer was successfully modified by ATRP. The feasibility of using the prepared polymer brush-grafted glass as a hepatocyte sheet fabrication dish was investigated using primary rat hepatocytes. The PVLA-b-PNIPAAm brushes exhibited hepatocyte adhesion and proliferation without FBS precoating. By reducing the temperature from 37 °C to 20 °C, the hepatocyte sheet was recovered from the copolymer brush. These results indicated that the prepared PVLA-b-PNIPAAm brushes can be utilized for effective hepatocyte sheet fabrication without the need for FBS precoating.