Phosphate buffer is widely used in biological and chemical research due to its ability to maintain a stable pH. It is commonly employed in cell culture applications to provide a consistent environment for cell growth and experiments. In molecular biology, it is used for DNA and RNA extraction, as well as in gel electrophoresis to stabilize pH during the process. It also plays a critical role in immunoassays, such as ELISA, by ensuring optimal conditions for antibody-antigen interactions. Additionally, phosphate buffer is utilized in diagnostic kits and medical testing to maintain the integrity of samples and reagents. Its compatibility with biological systems makes it a preferred choice for various laboratory procedures.