A quantitative microassay for in‐vitro toxicity testing of biomaterials

Abstract

A quantitative tissue culture method is described for toxicity testing of biomaterials. The material to be evaluated, or in the case of insoluble materials—an extract of the material, is incubated on a monolayer of fibroblasts in 24 well culture plates. The activity of the fibroblasts is ascertained by measuring the rate of mitosis (³H‐thymidine incorporation), the synthesis of glycosaminoglycans (³⁵SO incorporation) or production of total protein (³H‐tryptophan incorporation). By proper choice of label, the effect of the biomaterial on cellular proliferation or production of macromolecules or both may be assessed. Materials with a cytotoxic effect cause inhibition of incorporation of radioactive label in the above assays. The cell monolayers can also be inspected microscopically for evidence of cytotoxicity. The method is quantitative, simple, reproducible, rapid, and suitable for screening of a large number of samples.