Phosphate buffer is widely used in biological and chemical research to maintain stable pH levels in various experiments. It is commonly employed in cell culture applications to provide a consistent environment for cell growth and viability. In molecular biology, it is utilized during DNA and RNA extraction procedures to ensure optimal conditions for enzymatic reactions. The buffer is also essential in immunohistochemistry and immunofluorescence techniques, where it helps preserve the structure of tissues and cells while maintaining antibody activity. Additionally, phosphate buffer is used in diagnostic assays, such as ELISA, to stabilize reagents and enhance the accuracy of results. Its ability to mimic physiological conditions makes it a key component in drug development and pharmacokinetic studies.