Dopamine, the protagonist of mussel-inspired bio-adhesive molecule, can oxidize and polymerize spontaneously under alkaline condition to form a thin polydopamine (PDA) coating on various materials. PDA has good biocompatibility , and contains abundant functional groups that can facilitate further loading of interesting biomolecules. Moreover, PDA has strong absorption in the whole ultraviolet-visible (UV-vis) light range , suggesting its potential use as a generic fluorescence quencher.