In vitro biocompatibility testing of polylactides

Abstract

Four high-molecular weight polylactides, three poly-l-lactides of 100, 250 and 500 kDa and a poly-dl-lactide of 400 kDa, were tested qualitatively in vitro. Cells were cultured on polylactide films and with media based on the artificially aged polylactides, as well as with different concentrations of the final degradation products (monomers). Implant site-related cell types were selected. Three kinds of epithelial cells (middle ear, ear canal and nasal septum) as well as fibroblasts and osteosarcoma cells were used. Characteristic of all four polylactides was the normal morphology of cells when cultured on polylactide films and with the artificially ageing media. Although the polylactide films revealed still uncovered spots after 14 days culture, the control cultures were already confluent. The different concentrations of monomers revealed normal cell morphologies except for the 10 mg ml-1 concentration, which showed larger fibroblasts, and the nasal septum epithelium showed more signs of terminal differentiation for the 10 mg ml-1 d-monomer than was seen for the l-monomer even if the osmolarity was adjusted. The degradation products of polylactide are not expected to cause adverse reactions when implanted, since cell cultures with monomer concentrations up to 1 mg ml-1 resulted in normal morphologies. In the present study the cells were not able to cover the polylactide films completely.