In vitro biocompatibility of degradable biopolymers in cell line cultures from various ocular tissues: extraction studies

In vitro biocompatibility of 50:50 PDLGA, 85:15 PDLGA, and Inion GTR (TM) membrane was evaluated in cell line cultures from various ocular tissues, in human corneal epithelial cells (HCE), rabbit stromal fibroblasts (SIRC), bovine corneal endothelial cells (BCE), human conjunctival epithelial cells (IOBA-NHC), and human retinal pigment epithelial cells (ARPE-19). To study the toxicity of degradation products, the biomaterials were extracted in phosphate buffered saline at 70 degrees C for 24 h. The cell cultures were exposed to biomaterial extract diluted in medium (1:1-1:8) and the biocompatibility was evaluated by the WST-1 cytotoxicity/cell proliferation test. In all experiments without pH neutralization, cell viability increased with decreasing biomaterial extract volume. The highest extraction ratio 1:1 of PDLGA 50:50 decreased viability from 5-20%, from the control level, depending on the cell type. The corresponding cell viability values for PDLGA 85:15 and Inion GTR membrane ranged from 47-87% and 66-92%, respectively. When the pH of biomaterial extract was neutralized, Inion GTR membrane and PDLGA 85:15 had no effect on viability. BCE, HCE, and IOBA-NHC appeared to the most sensitive cell types, while SIRC and ARPE-19 were more resistant. The results of our in vitro studies suggest that the polymers tested are satisfactorily biocompatible.