A sensitive plasmonic copper(II) sensor based on gold nanoparticles deposited on ITO glass substrate

Gold nanoparticles (Au NPs) based plasmonic probe was developed for sensitive and selective detection of Cu2+ ion. The Au NPs were self-assembled on transparent indium tin oxide (ITO) film coated glass substrate using poly dimethyl diallyl ammonium chloride (PDDA) as a linker and then calcined at 400 degrees C to obtain pure Au NPs on ITO surface (ITO/Au NPs). The probe was fabricated by functionalizing L-cysteine (Cys) on to gold surface (ITO/Au NPs/Cys). The strong chelation of Cu2+ with Cys formed a stable Cys-Cu complex, and resulted in the red-shift of localized surface plasmon resonance (LSPR) peak of the Au NPs. The introduction of bovine serum albumin (BSA) as the second complexant could form complex of Cys-Cu-BAS and further markedly enhanced the red-shift of the LSPR peak. This plasmonic probe provided a highly sensitive and selective detection towards Cu2+ ions, with a wide linear detection range (10(-11)-10(-5) M) over 6 orders of magnitude. The simple and cost-effective probe was successfully applied to the determination of Cu2+ in real samples. (C) 2016 Elsevier B.V. All rights reserved.