Cytocompatibility

Cytocompatibility is a measure of how compatible a material or substance is with living cells. It describes the ability of the material to support cell survival, adhesion, proliferation and function while not causing cytotoxic effects. Cytocompatibility is a component of the broader concept of biocompatibility, focusing specifically on cellular responses to materials, surfaces, or extracts.

Assessment is typically performed in vitro using cell-based assays. Common approaches include direct contact tests and extract tests, with cytotoxicity assays such as MTT, XTT, resazurin reduction, or lactate dehydrogenase release. Endpoints include cell viability, attachment and spreading, morphology, and proliferation. Testing conditions, including cell type, exposure duration, and material preparation, influence results. Standards such as ISO 10993-5 provide guidance for cytotoxicity testing.

Factors affecting cytocompatibility include material composition, surface chemistry, energy and wettability, roughness and topography, and the stability of the material or its degradation products. Sterilization methods, leachables, and interactions with biological fluids can also alter cellular responses. Surface modification, coatings, and functionalization are often used to enhance cytocompatibility.

Applications of cytocompatibility evaluation include medical implants, dental materials, tissue engineering scaffolds, and substrates for cell culture. A material may be cytocompatible but not fully biocompatible in vivo, due to immune or systemic reactions; thus cytocompatibility is necessary but not sufficient for overall biocompatibility.

In practice, regulatory and research contexts rely on standardized testing to compare materials and guide design choices. Additional standards address broader biocompatibility and specific endpoints.