Mal-PEG6-acid is widely used in bioconjugation and chemical biology for attaching biomolecules, such as proteins, peptides, or antibodies, to other entities like drugs, dyes, or nanoparticles. Its maleimide group reacts selectively with thiol groups (-SH) in cysteine residues, enabling precise and stable linkages. The PEG6 spacer enhances solubility, reduces steric hindrance, and improves biocompatibility, making it ideal for creating targeted drug delivery systems, diagnostic probes, or therapeutic conjugates. It is particularly valuable in antibody-drug conjugates (ADCs) and biopharmaceutical research, where controlled and efficient conjugation is critical.