CHO-PEG-COOH is widely used in bioconjugation and drug delivery systems due to its reactive aldehyde (CHO) and carboxylic acid (COOH) groups. The aldehyde group enables selective conjugation with amine-containing molecules, such as proteins or peptides, under mild conditions, while the carboxylic acid group allows further functionalization or coupling with other molecules. This compound is particularly valuable in the development of targeted drug delivery systems, where it helps in attaching therapeutic agents to carriers like nanoparticles or liposomes. Additionally, it is utilized in surface modification of materials for biomedical applications, enhancing biocompatibility and enabling specific interactions with biological systems. Its PEG (polyethylene glycol) segment provides solubility, stability, and reduced immunogenicity, making it a versatile tool in pharmaceutical and biotechnological research.