Colorimetric determination of DNA concentration and mismatches using hybridization-mediated growth of gold nanoparticle probes

A novel colorimetric approach to sense DNA samples was demonstrated successfully based on a concept of hybridization-mediated growth of gold nanoparticles probes (AuNP probes). The growth size and conformation of the probes are dominated by DNA samples that hybridize with the probes. The growth probes serve as nanoparticle biosensors that can be utilized to analyze concentrations of DNA samples or to discriminate mismatches of DNA samples to the probes (complementarity of DNA) in terms of size- and shape-dependence optical properties. By means of the proposed method, not only the semi-quantitation of target DNA but also the differentiation of DNA mismatches can be readily achieved with a naked eye or simple spectrophotometer. This method features small consumption of reagents, a satisfactory detection limit (about 60 nM), a small duration of assay (a couple of minutes), and a simple procedure without thermal control.