Thermoresponsive cellulosic hydrogels with cell-releasing behavior.

Here we report the preparation and characterization of thermoresponsive cellulosic hydrogels with cell-releasing behavior. Hydroxypropyl cellulose (HPC) was modified with methacrylic anhydride (MA). The resultant macromonomer, HPC-MA, retains the characteristic thermoresponsive phase behavior of HPC, with an onset temperature of 36 °C and a lower critical solution temperature (LCST) of 37-38 °C, as determined by turbidity measurement. Homogenous HPC-MA hydrogels were prepared by UV-cross-linking the aqueous solutions of the macromonomer at room temperature, and characterized by water contact angle and swelling ratio measurements, and dynamic mechanical analysis. These hydrogels exhibit temperature-dependent surface hydrophilicity and hydrophobicity, equilibrium water content as well as mechanical properties. Cell-releasing characteristics were demonstrated using African green monkey kidney cell line (COS-7 cells) and murine-derived embryonic stem cell line (Oct4b2). By reducing temperature to 4 °C, the cultivated cells spontaneously detached from the hydrogels without the need of trypsin treatment. These unique properties make our HPC-MA hydrogels potential substrates for cell sheet engineering.