**2. Parameters used in cell-based assays**

Cell-based toxicological assays are designed to evaluate the potential toxic effects of various substances, including drugs, chemicals, and environmental pollutants, on living cells. These assays measure a range of cellular parameters that can be affected by toxic agents. By examining these factors in cell-based toxicological assays, researchers can gain a comprehensive understanding of the effects of various substances on cells and identify potential therapeutic targets, mechanisms of action, and potential side effects [2]. This information is crucial for the development of safer and more effective drugs, chemicals, and other products. Here are some common parameters used in cell-based toxicological assays:

### **2.1 Cell viability**

Cell viability is a measure of the number of living cells in a sample. Cell viability assays are crucial for determining the overall health and survival of cells in response to various treatments. These assays are based on cellular functions that are specific to living cells, such as metabolic activity or membrane integrity [3]. A decrease in

*Cytotoxicity and Cell Viability Assessment of Biomaterials DOI: http://dx.doi.org/10.5772/intechopen.111822*

viability indicates a toxic effect, whereas an increase may indicate a protective or stimulatory effect. Several assays, such as MTT, XTT, WST-1, Neutral Red, and Alamar Blue, can be used to assess cell viability based on metabolic activity, dye uptake, or ATP levels. Damage to the cell membrane can be identified by the presence of intracellular substances, like lactate dehydrogenase (LDH), in the suspension medium. This can be assessed when cells are in contact with materials or material extracts in cell cultures [4]. A decline in metabolic activity might signal cell death before the breakdown of the membrane occurs. The MTT assay, introduced by Mosmann, is a widely used technique for evaluating cell viability [5].
