Simultaneous detection of four specific DNAs fragments based on two-dimensional bimetallic MOF nanosheets

We have developed quantitative analysis method for simultaneous detection of four specific DNAs fragments based on two-dimensional bimetallic MOF nanosheets Co/Fe(1:1) MOF. In this analytical method, four different dyes were labeled on the complementary sequences of four different target DNAs (T-DNAs) as fluorescent probes, and Co/Fe(1:1) MOF was chosen as quencher. In the absence of T-DNAs, four fluorescent probes were adsorbed on the Co/Fe(1:1) MOF by π-π stacking, and the dyes were close to Co/Fe(1:1) MOF, their fluorescence is quenched by Co/Fe(1:1) MOF through photoinduced electron transfer. In the presence of T-DNAs, four different T-DNAs react with the corresponding fluorescent probe to form double strands DNA, which cannot be adsorbed by Co/Fe(1:1) MOF, and the fluorescence of dyes was recovered. Under the optimal conditions, the fluorescence intensities of four dyes all exhibited good linear dependence on corresponding concentration of T-DNAs. The detection limits of HAV, HBV, HCV and HIV were 0.032 nmol/L, 0.037 nmol/L, 0.53 nmol/L and 0.18 nmol/L (3σ, n = 9), respectively. The analytical method has low detection limit, good selectivity and high sensitivity, and can be used to detect T-DNAs in vitro.