This study describes the preparation and characterization of a biodegradable 3D hydrogel constructed from hydroxypropyl cellulose (HPC), modified with bifunctional methacrylic anhydride (MA) to form hydroxpropyl cellulose methacrylate (HPC-MA), for adipose tissue engineering applications. The hydrogels were prepared from three different concentrations (10 wt%, 15 wt% and 20 wt%) of HPC-MA with 0.35 degree of substitution. HPC-MA hydrogel scaffolds with open biphasic feature were prepared by exploiting the thermal responsive phase behavior of HPC and temperature mediated phase separation of HPC-MA. The resulting scaffolds exhibited pore size ranging from 30 to 300 µm and interconnected porosity of ~90 %. The swelling ratio (SR) and storage modulus of HPC-MA scaffolds were in the range of 12.94 -to 35.83 and 0.75 -to 4.28 kPa, respectively. The swelling ratio and storage modulus suggested that the scaffold exhibits high water retention, allowing medium exchange during cell culturing and suitable for adipose tissues regeneration. The HPC-MA scaffolds were found to be biocompatible to human adipose-derived stem cells (ASCs). ASCs were successfully differentiated into the adipocytes inside the scaffolds, and therefore demonstrated the potential application of these HPC-MA scaffolds for adipose tissue engineering.

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.