Colorimetric Detection of Nucleic Acids through Triplex-Hybridization Chain Reaction and DNA-Controlled Growth of Platinum Nanoparticles on Graphene Oxide.

Abstract

The controllable growth of metal nanoparticles on nanomaterials is becoming a useful strategy for developing nanocomposites with designated performance. Here, a DNA-controlled strategy for growth of Pt nanoparticles on graphene oxide (GO-PtNPs) to regulate the nanozyme activity and a triplex-hybridization chain reaction (tHCR) for triggering the assembly of DNA probes to amplify the target-induced nanozyme catalytic signal were designed. The tHCR with one linear and two hairpin probes could be specially triggered by a tHCR trigger to form a long double-stranded DNA structure in the presence of target nucleic acid, which hindered the adsorption of these probes on a GO surface, and thus accelerated the growth of PtNPs. The formed GO-PtNPs showed strong catalytic activity toward the oxidation of 3,3,5,5-tetramethylbenzidine, thereby producing an amplified "turn-on" detection signal. The proposed method showed very high sensitivity with the detection limits down to 14.6 pM for mutant KRAS DNA and 21.7 pM for let-7a microRNA. This method was validated with better analytical performance than a general HCR system and could be effectively used for the identification of single-nucleotide polymorphisms, thus providing a novel approach for simple and sensitive detection of nucleic acids.