Retinal pigment epithelium cell culture on thin biodegradable poly(DL-lactic-co-glycolic acid) films

Thin films of 50 : 50 and 75 : 25 poly(DL-lactic-co-glycolic acid) (PLGA) were manufactured with a controlled thickness of less than 10 μm. The effect of PLGA copolymer ratio on in vitro cell attachment, proliferation, morphology, and tight junction formation was evaluated using a human D407 retinal pigment epithelium (RPE) cell line. Almost complete cell attachment was achieved on both PLGA films after 8 h of cell seeding, which was comparable to that on tissue culture polystyrene (TCPS) controls. The initial cell seeding density affected attachment, and the optimal value for 50: 50 PLGA was 25 000 cells cm^-2. After 7 days of in vitro culture, cell density on 50 : 50 and 75 : 25 PLGA films increased 45 and 40 folds, respectively, and a 34-fold increase was observed on TCPS. The RPE cells cultured on PLGA films at confluence had a characteristic cobblestone morphology. Confluent RPE cells also developed normal tight junctions in vitro which were concentrated mainly at the apical surfaces of cell-cell junctions. These results demonstrated that thin biodegradable PLGA films can provide suitable substrates for human RPE cell culture, and may serve as temporary carriers for subretinal implantation of organized sheets of RPE.