Mal-amido-PEG12-NHS is a heterobifunctional crosslinker widely used in bioconjugation and chemical biology for attaching biomolecules to various substrates. It features a maleimide group for selective reaction with thiols (e.g., cysteine residues), an amide linker, a PEG12 spacer that enhances solubility and reduces steric hindrance, and an NHS ester for efficient reaction with primary amines (e.g., lysine residues), forming stable amide bonds. This dual functionality makes it ideal for linking proteins, peptides, antibodies, or other molecules to surfaces, nanoparticles, or drug carriers.

It is particularly valuable in drug delivery systems, facilitating targeted attachment of therapeutic agents to carriers while minimizing immune recognition. In diagnostic assays, it immobilizes detection molecules onto solid supports, enhancing sensitivity and specificity. Additionally, it supports research in bioconjugates, such as studying protein interactions, cellular uptake mechanisms, or developing targeted therapeutics.