Recognition of single-base mismatch DNA by Au nanoparticle-assisted electroelution.

A simple, convenient and effective method based on the surface plasmon resonance (SPR) technique was introduced for recognition of single-base mismatch DNA (smDNA) by Au nanoparticle (AuNPs)-assisted electroelution. In this method, target DNA, including perfectly matched DNA and smDNA, hybridized with the DNA probes immobilized on Au film and AuNPs, then the Au film was negatively charged. Owing to the difference in stability between single-base mismatch and perfect match DNA, effective distinction between complementary DNA (cDNA) and smDNA was achieved in the presence of an electric field: double-stranded DNA (dsDNA) formed between smDNA targets and DNA probes was denatured by the repulsion force acting on the negatively-charged DNA-linked AuNPs, while the perfectly matched duplex was not influenced. However, if the AuNPs were absent, the effects of cDNA and smDNA were not distinguishable. The effects of electric field intensity and mismatch sites were also investigated. All of the operations were performed under mild conditions. The results showed that AuNP-assisted electroelution may be exploited for the construction of biosensors with high selectivity.