Resonance light scattering determination of trace bisphenol A with signal amplification by aptamer–nanogold catalysis

HAuCl₄ was reduced by sodium citrate to prepare 10 nm gold nanoparticles (AuNPs) that were modified by the bisphenol A aptamer (Apt) to obtain an aptamer–nanogold probe (Apt‐AuNP) for bisphenol A (BPA). The probes were aggregated nonspecifically to form large clusters, which showed a strong resonance light scattering (RLS) peak at 520 nm, under preparation conditions (pH 7.6 Na₂HPO₄‐NaH₂PO₄ buffer and ultrasonication). Upon addition of BPA, the probe reacted specifically to form dispersed BPA‐Apt‐AuNP conjugates that exhibited strong catalysis of the two particle reactions of glucose‐Cu(II) and hydrazine hydrochloride‐Cu(II) with a strong RLS peak at 360 nm and 510 nm respectively. When the BPA concentration increased, the RLS intensity at 360 nm and 510 nm increased respectively. Accordingly, two new and highly‐sensitive RLS methods were established for the detection of BPA, using the Apt‐AuNP catalytic amplification. Copyright © 2013 John Wiley & Sons, Ltd.