Enzyme-degradable phosphorylcholine porous hydrogels cross-linked with polyphosphoesters for cell matrices

Biodegradable highly porous hydrogels composed of poly [2-methacryloyloxyethyl phosphorylcholine (MPC)] cross-linked with polyphosphoesters have been prepared as novel cellular matrices. Well-controlled porous hydrogels were fabricated by using potassium hydrogen carbonate as a porogen salt for forming gas. This process enabled the homogeneous expansion of pores within the polymer hydrogel matrices, leading to well-interconnected high porosity. The mechanical properties of the hydrogels were influenced by the cross-linking density and porous structure. Hydrolysis and enzymatic digestion of the hydrogels were determined under basic conditions. The cross-linking density and porosity influenced the rate of degradation of the hydrogels. Acceleration of the degradation with alkaline phosphatase was also observed. Cultivation of mouse osteoblastic cell (MC3T3-E1) was performed in the highly porous hydrogels and cell viability was well maintained. The rate of cell proliferation also was relatively increased with an increase in the amount of polyphosphoesters in the hydrogel. Basic fibroblast growth factor (bFGF) was physically absorbed by the hydrogels and effectively induced cell proliferation. In conclusion, the porous hydrogels prepared in this study contributed a suitable environment for three-dimensional cell cultivation and may be useful for cell and tissue matrices. (c) 2006 Elsevier Ltd. All rights reserved.