Effect of PEG-PLLA diblock copolymer on macroporous PLLA scaffolds by thermally induced phase separation.

A regular and highly interconnected macroporous poly(L-lactic acid) (PLLA) scaffold was fabricated from a PLLA-dioxane-water ternary system with added polyethylene glycol (PEG)-PLLA diblock using thermally induced phase separation (TIPS). The morphology of the scaffold was investigated in detail by controlling the following TIPS parameters: quenching temperature, aging time, polymer concentration, molecular structure, and diblock concentration. The phase diagram was assessed visually on the basis of the turbidity. The cloud-point curve shifted to higher temperatures with increasing PEG content in the additives (PEG-PLLA diblocks), due to a stronger interaction between PEG and water in solution. The addition of diblock series (0.5 wt% in solution) stabilized interconnections of pores at a later stage without segregation or sedimentation. The pore size of the scaffold could be easily controlled in the range 50-300 microm. A macroporous PLLA scaffold was used to study an MC3T3-E1 cell (an osteoblast-like cell) culture. The cells successfully proliferated in the PLLA scaffold in the presence of added PEG-PLLA diblock for 4 weeks.