Combination of aptamer with gold nanoparticles for electrochemical signal amplification: Application to sensitive detection of platelet-derived growth factor

In this paper, we report a novel electrochemical detection approach for platelet-derived growth factor (PDGF) via sandwich structure and gold nanoparticles (Au-NPs) mediated amplification technique. The sandwich structure is fabricated based on the fact that PDGF has two aptamer-binding sites, which makes it possible for one PDGF molecule to connect with two aptamers simultaneously. It is found that this electrochemical system with sandwich structure and Au-NPs can significantly amplify the signal of electrochemical probe (Ru(NH3)(5)Cl](2+) for PDGF detection, and thus increase the detection sensitivity significantly. As a result, this PDGF detection approach obtains an extraordinarily low detection limit of 1 x 10(-14) M for purified samples, 1 x 10(-12) M for contaminated-ridden samples or undiluted blood serum. This detection approach can also exhibit good stability and excellent specificity. (C) 2008 Elsevier B.V. All rights reserved.