Ferrocene-Doped Polystyrene Nanoenzyme and DNAzyme Cocatalytic SERS Quantitative Assay of Ultratrace Pb(2+)

A new, stable and high-catalytic activity ferrocene-doped polystyrene nanosphere (PN(Fer)) sol was prepared by the hydrogel procedure and characterized by electron microscopy and molecular spectroscopy. Results show that the nanosol exhibits excellent catalysis of the new indicator nanoreaction between AgNO(3) and sodium formate to generate nanosilver with strong surface-enhanced Raman scattering (SERS), resonance Rayleigh scattering (RRS) and surface plasmon resonance absorption (Abs) trimode molecular spectral signals. This new nanocatalytic amplification trimode indicator reaction was coupled with the G-quadruplex DNAzyme catalytic amplification of Pb(2+) aptamer to fabricate a new SERS quantitative/RRS/Abs assay platform for the determination of ultratrace amounts of Pb(2+). The Pb(2+) content in water samples was analyzed with satisfactory results.