Highly sensitive and selective detection of single-nucleotide polymorphisms using gold nanoparticle MutS enzymes and a micro cantilever resonator

Mutant DNAs are important markers useful for the diagnosis of human disease. Single-nucleotide polymorphisms (SNPs) represent the most common types of DNA mutations. As there is only a one base pair change in a single nucleotide between the SNP and the wild-type DNA, it is difficult to distinguish the SNPs. In this report, a highly sensitive and selective detection and discrimination of SNPs is performed using MutS, gold nanoparticles (AuNP) and a resonator. A single mismatched base exists between the SNP mutation and the probe DNA on the resonator, and MutS binds to the DNA at the location of the mismatch. As MutS is attached to AuNP (MutS-AuNP), both MutS and AuNP are adsorbed onto the resonator. The detection is based on the resonance frequency shift of the resonator following the adsorption of MutS-AuNP on the resonator. Highly sensitive detection of DNA mutations was achieved using AuNPs that act as mass amplifiers, and the obtained limit of detected was 100 fM. Additionally, our proposed method detected mutations in the presence of as little as 0.1% wild-type, and discrimination of specific mutations was also achieved. The results obtained from our proposed method suggest its potential for diagnosing cancer patients.