Amino-PEG6-acetic acid is widely used in bioconjugation and pharmaceutical research due to its unique spacer and functional group properties. The long, hydrophilic PEG6 (polyethylene glycol) chain enhances solubility in aqueous and polar solvents, reducing aggregation and improving biocompatibility. This makes it ideal for modifying peptides, proteins, and small molecule drugs where increased solubility and reduced immunogenicity are desired.

The primary amine group allows for easy coupling to carboxylic acids via amide bond formation using standard coupling reagents, enabling attachment to targeting ligands, fluorophores, or solid supports. The terminal acetic acid group provides a second site for conjugation, often used to link payloads such as drugs, chelators, or labeling agents in the development of antibody-drug conjugates (ADCs), imaging probes, and targeted therapeutics.

It is also employed in the synthesis of PROTACs (proteolysis-targeting chimeras), where it acts as a linker connecting the E3 ligase ligand to the target protein binder, with the PEG spacer improving pharmacokinetic properties and cellular permeability. Additionally, its use in surface functionalization of nanoparticles and biosensors helps reduce non-specific binding while maintaining molecular accessibility.

Overall, Amino-PEG6-acetic acid is a versatile building block in medicinal chemistry and bioconjugate design, valued for its flexibility, hydrophilicity, and dual functionality.