A novel and highly sensitive nanocatalytic surface plasmon resonance-scattering analytical platform for detection of trace Pb ions

Gold nanoparticles (AuNP) have catalysis on the reaction of HAuCl4-H2O2. The produced AuNP have strong resonance Rayleigh scattering (RRS) effect and surface-enhanced resonance Raman scattering (SERS) effect when Victoria blue B (VBB) and rhodamine S (RhS) were used as probes. The increased RRS/SERS intensity respond linearly with the concentration of gold nanoparticles (AuNPB) which synthesized by NaBH4 over 0.038-76 ng/mL, 19-285 ng/mL, 3.8-456 ng/mL respectively. Four kinds of tested nanoparticles have catalysis on the HAuCl4-H2O2 particles reaction. Thus, a novel nanocatalysis surface plasmon resonance-scattering (SPR-S) analytical platform was developed for AuNP. The DNAzyme strand hybridized with the substrate strand to form double-stranded DNA (dsDNA) which couldn't protect AuNPc to aggregate to AuNPc aggregations, having strong RRS effect. Upon addition of Pb2+, dsDNA could be cracked by Pb2+ to produce single-stranded DNA (ssDNA) that adsorbed on the AuNPc surface to form AuNPc-ssDNA conjugates. The conjugates have strong catalysis on HAuCl4-H2O2 reaction. With increased Pb2+ concentration, the concentration of AuNPc-ssDNA increased and lead to the catalytic activity stronger. The increased RRS intensity responds linearly with Pb2+ concentration over 16.7-666.7 nmol/L. The SERS intensity responded linearly with the concentration of Pb2+ over 50-500 nmol/L.