Cell-based assays are laboratory techniques that use living cells to study biological processes and the effects of substances, such as drugs. These assays help researchers understand how cells respond to various stimuli, including chemicals, hormones, or genetic changes. They are essential for drug discovery, toxicity testing, and understanding disease mechanisms. These assays can be performed in various formats, including microplate systems, which allow for high-throughput screening of multiple samples simultaneously. By measuring cellular responses, such as cell viability, proliferation, or gene expression, scientists can gather valuable data that informs the development of new therapies and treatments.