Cross-Linker Containing A Photoreactive Azido Group

N-Succinimidyl 5-azido-2-nitrobenzoate (1) is a cross-linker containing both an N-succinimidyl group and a photoreactive azido group in same molecule. The former can bind with amino groups and the latter with adjacent substrates to form covalent bonding via photoexcitation. For example, Schöning et al. have reported the penicillin-sensitive biosensor fabricated by modifying amino groups of Si₃N₄ surface on a plate using 1, followed by immobilizing penicillinase to the azido moiety after UV irradiation. Besides this, it has been reported that 1 links to the N-terminal of poly-L-lysine and alginate beads microencapsulating living cells which are coated with poly-L-lysine by photo-cross-linking.