The Acid-PEG6-t-butyl ester is widely used in bioconjugation and drug delivery systems. Its PEG (polyethylene glycol) spacer enhances solubility and stability of conjugated molecules, making it valuable in pharmaceutical research. It acts as a linker in antibody-drug conjugates (ADCs), enabling targeted delivery of therapeutic agents to specific cells. The t-butyl ester group provides protection for the carboxylic acid, allowing controlled release or activation of the compound under specific conditions. This chemical is also utilized in peptide synthesis and protein modification, improving bioavailability and reducing immunogenicity. Additionally, it finds applications in nanotechnology for surface functionalization of nanoparticles, enhancing their biocompatibility and targeting efficiency.