In vitro cytotoxicity and cytocompatibility assays for biomaterial testing under regulatory platform

One of the main prerequisites to quality of a biomaterial for clinical use is the biocompatibility evaluation at the cellular and tissue levels. The primary and mandatory element in biocompatibility evaluation is cytotoxicity testing, which demonstrates the way in which cultured cells are exposed directly to the test material or to the extract of the test material. These endpoint tests look for damage on cultured cells at levels such as it morphology, growth, and metabolism. The decision on confirming a biomaterial to be cytotoxic depends upon a series of steps that are chosen on the basis of the nature of the biomaterial and the site and the nature of its application. Cytotoxicity tests are conducted on all biomaterials, implants, and raw materials for medical devices that are expected to be in contact with patients as a screening test. The test is also done for materials that are in the process of validation in cleaning, residual analysis, and batch evaluation during manufacturing. The International Organization for Standardization provides guidelines for the cytotoxicity testing of biomaterials and devices. The American Society for Testing and Materials and the United States Pharmacopeia–National Formulary recommend that the material or device be tested for biocompatibility with cells in vitro. In general, these in vitro cytotoxicity and cytocompatibility assays are fast, cost-effective, and useful for the initial screening of materials. In this chapter, various qualitative, semiquantitative, and quantitative tests that are routinely used for the regulatory platforms are explained.