A novel biosensor based on Au@Ag core-shell nanoparticles for SERS detection of arsenic (III).

In this work, we propose for the first time a simple and novel approach based on SERS and As (III) -aptamer for detection of As (III) with excellent selectivity and sensitivity. To maintain the wonderful SERS substrate, Au@Ag shell-core nanoparticle has been successfully synthesized by seeds growth method. As-prepared Au@Ag not only has well-dispersed but also obtains high SERS efficiency. The novel As (III) biosensor has an excellent linear correlation with the concentration of As (III) ranging from 0.5 to 10 ppb. The detection limit of this assay for As (III) is 0.1 ppb (3 times standard deviation rules) which is lower than the maximum limitation guided by the United States Environmental Protection Agency (EPA) and the World Health Organization (WHO). Importantly, the results were demonstrated that no other ions interfered with the detection of As (III) in water. Further, this As (III) biosensor was demonstrated in monitoring As (III) in lake water samples with satisfactory results.