WETTING OF POLY(L-LACTIC ACID) AND POLY(DL-LACTIC-CO-GLYCOLIC ACID) FOAMS FOR TISSUE-CULTURE

Biodegradable foams of hydrophobic polymers can be efficiently wet by two-step immersion in ethanol and water, which overcomes the hindered entry of water into air-filled pores. Ethanol readily enters into the porous polymer, after which it is diluted and replaced by water. This method was evaluated for porous disks of poly(L-lactic acid) (PLLA) and poly(DL-lactic-co-glycolic acid) (PLGA) foams of copolymer ratios 85:15 and 50:50. For PLLA disks of 0.88 porosity and 1730 mu m thickness, prewetting with ethanol for 1 h increased the percentage of void volume filled with water after 48 h from 23 to 79%. The same enhanced entry of water was also observed for prewet PLGA 85:15 disks of 0.86 porosity and 1300 mu m thickness, which exhibited an increase from 59 to 97% void volume occupied by water. Furthermore, the water entry even after 1 h was very close to its plateau value for all prewet polymers tested. In recent studies, this method has been useful in uniformly seeding three-dimensional biodegradable polymer substrates for cell and tissue culture.