Used extensively in cell culture and biological research to maintain a stable pH and osmotic balance. It is ideal for washing cells during experiments, as it does not contain calcium or magnesium, which could interfere with certain assays or enzymatic reactions. Commonly employed as a diluent or buffer in immunoassays, flow cytometry, and other laboratory procedures. Its lack of phenol red makes it suitable for applications where dye interference is a concern, such as fluorescence microscopy or spectrophotometry. Also used in vaccine production and biopharmaceutical processes for rinsing or suspending cells.