Characterization of genomic single nucleotide polymorphism via colorimetric detection using a single gold nanoprobe.

Identification of specific nucleic acid sequences mediated by gold nanoparticles derivatized thiol-modified oligonucleotides (Au-nanoprobes) has been proven to be a useful tool in molecular diagnostics. Here, we demonstrate that, on optimization, detection may be simplified via the use of a single Au-nanoprobe to detect a single nucleotide polymorphism (SNP) in homo- or heterozygote condition. We validated this non-cross-linking approach through the analysis of 20 clinical samples using a single specific Au-nanoprobe for an SNP in the FTO (fat mass and obesity-associated) gene against direct DNA sequencing. Sensitivity, specificity, and limit of detection (LOD) were determined, and statistical differences were calculated by one-way analysis of variance (ANOVA) and a post hoc Tukey's test to ascertain whether there were any differences between Au-nanoprobe genotyped groups. For the first time, we show that the use of a single Au-nanoprobe can detect SNP for each genetic status (wild type, heterozygous, or mutant) with high degrees of sensitivity (87.50%) and specificity (91.67%).