DBCO-PEG6-NHS ester is a click chemistry PEG reagent containing an NHS ester that reacts specifically with primary amines, such as side chains of lysine residues or aminosilane-coated surfaces, under neutral or slightly alkaline conditions. , efficient reaction to form covalent bonds. DBCO-PEG6-NHS ester also contains a DBCO group that can undergo strain-promoted alkyne-azide cycloaddition (SPAAC) with molecules containing Azide groups^[1].