Resonance Rayleigh scattering detection of trace PDGF based on catalysis of an aptamer-modified nanogold probe in the Fehling reaction

Abstract

Gold nanoparticles (GN) were modified by a platelet-derived growth factor (PDGF) aptamer to obtain stable aptamer-nanogold probes (Apt-GN). The probes specifically combined with PDGF-AA to form Apt-GN–PDGF-AA clusters that exhibited a resonance Rayleigh scattering (RRS) peak at 550 nm. The RRS intensity ΔI550nm was linear to the PDGF-AA concentration in the range of 0.33–40 ng mL−1. The probes exhibit strong catalysis of the Fehling reagent–glucose Cu2O particle reaction that can be monitored by the RRS technique at 610 nm, but the cluster is very weak. When PDGF-AA concentration increased, the Apt-GN decreased, and the RRS intensity at 610 nm decreased. The decreased RRS intensity ΔI610nm was linear to PDGF-AA concentration in the range of 0.03–26.67 ng mL−1. Accordingly, two new aptamer-nanogold RRS methods were established.