Used in bioconjugation and labeling applications, particularly in the field of molecular biology and biochemistry. It serves as a fluorescent probe due to the FITC (fluorescein isothiocyanate) component, enabling visualization and tracking of biomolecules in various assays. The PEG4 spacer enhances solubility and reduces steric hindrance, improving the efficiency of conjugation. The carboxylic acid (COOH) group allows for covalent attachment to amines or other reactive groups on target molecules, such as proteins, peptides, or antibodies. Commonly applied in fluorescence microscopy, flow cytometry, and immunoassays for studying cellular processes, protein interactions, and drug delivery systems.