OSTEOBLAST FUNCTION ON SYNTHETIC BIODEGRADABLE POLYMERS

Rat osteoblasts were cultured on films of biodegradable poly(L-lactic acid) (PLLA), 75:25 poly(DL-lactic-co-glycolic acid) (PLGA), 50:50 PLG A, and poly(glycolic acid) (PGA) for up to 14 days. Osteoblasts attach ed equally well to all the polymer substrates after 8 h in culture. By day 4 in culture, osteoblasts had exceeded confluency numbers, and th eir proliferation leveled off by day 7. An increase in alkaline phosph atase (ALP) activity from 1.92(+/-0.47) x 10(-7) for day 7 to 5.75 (+/ -0.12) x 10(-7) mu mol/cell per min for day 14 was reported for osteob lasts cultured on 75:25 PLGA, which was comparable to that observed fo r tissue culture polystyrene (TCPS) controls. The ALP activities expre ssed by osteoblasts cultured on PLLA, 50:50 PLGA, and PGA films did no t significantly increase over time. Collagen synthesis for osteoblasts cultured on all polymer substrates was similar to that of TCPS and di d not vary with time. The morphology of cultured osteoblasts was not a ffected by the continuous degradation of the polymer substrates. These results demonstrate that poly(ol-hydroxy esters) can provide a suitab le substrate for osteoblast culture and hold promise in bone regenerat ion by osteoblast transplantation. (C) 1994 John Wiley and Sons, Inc.