Resonance Rayleigh scattering spectral method for determination of urinary 8-hydroxy-2′-deoxyguanosine using gold nanoparticles as probe

A simple, novel and sensitive method was developed to determine 8-hydroxy-2'-deoxyguanosine (8-OHdG), a biomarker of DNA oxidation damage in human urine. This method was based on that 8-OHdG can combined with gold nanoparticles (AuNPs) and enhance the resonance Rayleigh scattering (RRS) intensity of them, and the enhanced RRS intensity is linearly correlated with the concentration of 8-OHdG added over the range of 1.0 x 10(-11)-2.0 x 10(-9) mol L-1. The absorption spectrum and RRS spectrum of the AuNPs-8-OHdG system were analyzed. Parameters that affect the RRS intensities such as pH value, concentration of AuNPs, mixing sequence of the reagents, and coexisting substances were systematically investigated and optimized. The limit of detection (LOD) was 3.0 x 10(-12) mol L-1. Interference tests showed that the method developed had very good selectivity and could be used conveniently to determine urinary 8-OHdG without any complicated or time-consuming sample pretreatment processes. Possible mechanisms for the RRS enhancement of AuNPs-8-OHdG system were discussed, and it thought that the volume increase of AuNPs which caused by various reactions between in AuNPs and 8-OHdG were the fundamental factors. (C) 2012 Elsevier B.V. All rights reserved.