Cell-Culture Cytotoxicity Testing of Candidate Device Materials

In vitro cytotoxicity evaluation of candidate materials for medical devices is described. Materials and material extracts are added to freshly seeded human embryonic lung fibroblast (IMR-90) cell cultures. Both negative control and positive control materials are included in each evaluation of test materials. The negative control material does not cause detectable cytotoxicity to the cell system, and the positive control material causes cytotoxic effects.

Controls are used to monitor the cell system over time and detect any changes in the system that would alter the testing results. Results are scored on the basis of degree of morphological deterioration of cells and time required to obtain maximum deterioration. Candidate materials are evaluated comparatively in terms of their relative lack of cytotoxic effects on cell culture. Final results are not interpreted on a pass/fail basis but in terms of which materials are most likely to demonstrate biocompatibility in vivo.

This paper also reviews the need to develop specific cell-culture cytotoxicity assays on the basis of the intended end use of the material being evaluated. Some historical information concerning endothelial cell-culture systems and the need to develop a standardized cytotoxicity assay for blood contact materials is reviewed.