Facile preparation of fluorescent polydihydroxyphenylalanine nanoparticles for label-free detection of copper ions

Abstract In this work, we developed an effective and convenient fluorescent Cu 2+ detection method using polydihydroxyphenylalanine nanoparticles (PDNPs) as nanoprobes. The fluorescent PDNPs were facilely prepared by autopolymerization of dihydroxyphenylalanine under alkaline condition. The fluorescence of the PDNPs could be quenched by Cu 2+ . The PDNP nanoprobe is low cost and simple, and does not require further post-modification with Cu 2+ specific recognition units. In addition, this nanoprobe exhibits high sensitivity and the detection limit is well below the safety limit of Cu 2+ in drinking water permitted by the U.S. Environmental Protection Agency. Furthermore, the sensing system is also easy to implement, fast, and selective. Satisfactory detection of Cu 2+ in river water samples were observed, demonstrating the potential practical applications.