Chemically Crosslinked Methylcellulose Substrates for Cell Sheet Engineering

Methylcellulose (MC) hydrogels have been successfully proposed in the field of cell sheet engineering (CSE), allowing cell detachment from their surface by lowering the temperature below their transition temperature (T(t)). Among the main limitations of pristine MC hydrogels, low physical stability and mechanical performances limit the breadth of their potential applications. In this study, a crosslinking strategy based on citric acid (CA) was used to prepare thermoresponsive MC hydrogels, with different degrees of crosslinking, to exploit their possible use as substrates in CSE. The investigated amounts of CA did not cause any cytotoxic effect while improving the mechanical performance of the hydrogels (+11-fold increase in E, compared to control MC). The possibility to obtain cell sheets (CSs) was then demonstrated using murine fibroblast cell line (L929 cells). Cells adhered on crosslinked MC hydrogels’ surface in standard culture conditions and then were harvested at selected time points as single CSs. CS detachment was achieved simply by lowering the external temperature below the T(t) of MC. The detached CSs displayed adhesive and proliferative activity when transferred to new plastic culture surfaces, indicating a high potential for regenerative purposes.