A colorimetric method for H1N1 DNA detection using rolling circle amplification.

A highly sensitive and specific colorimetry-based rolling circle amplification (RCA) assay has been successfully developed as a method for the effective detection of H1N1 DNA. Specific oligonucleotide and reporter primer probes were designed together with a circular template, and the oligonucleotide probes were attached to the surfaces of magnetic beads (MBs) to form functional MB-DNA conjugates as capture probes for the target H1N1 DNA molecules. Together with the addition of DNA targets and reporter primer probes to the MB-DNA conjugates, sandwiched hybrids were formed. The initiation of RCA amplification using the circular template in the presence of phi29 polymerase allowed for the amplification of a large number of repeat sequences of the single-stranded (ss)-DNA product. This RCA product accumulated gold nanoparticles (AuNPs), resulting in a colorimetric change that could be viewed by the naked eye or detected using UV-vis spectroscopy. According to this method, H1N1 DNA could be detected at the 1 pmol L(-1) level. This platform exhibited design convenience, simplicity, and cost-effectiveness, and could be used to provide a new diagnostic assay for H1N1, and other infectious diseases.