Highly Sensitive Resonance Scattering Detection of DNA Hybridization Using Aptamer-Modified Gold Nanopaticle as Catalyst

Abstract

Gold nanoparticle particles in size of 10 nm were used to label the thiol-modified single-stranded DNA aptamer (SH-ssDNA) to obtain an aptamer-modified gold nanoparticle probe (AussDNA) for target DNA (tDNA). In pH 7.4 NaH2PO4–Na2HPO4 buffer solution, the hybridization reaction between AussDNA and tDNA took place to form larger aptamer-modified gold nanoparticle cluster complex. The excess aptamer-modified gold nanoparticle probe in the supernatant solutions was obtained by centrifuging and can be used as nanocatalyst for the 0.276 mmol/L CuSO4-65.4 mmol/L potassium-sodium tartrate-0.37 mmol/L glucose system at 70 °C. The cubic Cu2O particles generated by the nanocatalytic reducing exhibit a strong resonance scattering (RS) peak at 620 nm. In the selected conditions, the RS intensity at 620 nm decreased with addition of tDNA, and the decreased intensity ΔI 620 nm is proportional to tDNA concentration (C tDNA) from 0.12 to 72 pM, with regress equation of ΔI 620 nm = 1.29C tDNA + 4.05, correlation coefficient of 0.9917, and detection limit of 0.084 pM tDNA.