Silver nanoparticles fluorescence enhancement effect for determination of nucleic acids with kaempferol-Al(III)

Nucleic acids can greatly enhance fluorescence intensity of the kaempferol (Km)-Al(III) system in the presence of silver nanoparticles (AgNPs). Based on this, a novel method for the determination of nucleic acids is proposed. Under studied conditions, there are linear relationships between the extent of fluorescence enhancement and the concentration of nucleic acids in the range of 5.0 × 10^?9 to 2.0 × 10^?6 g mL^?1 for fish sperm DNA (fsDNA), 7.0 × 10^?9 to 2.0 × 10^?6 g mL^?1 for salmon sperm DNA (smDNA) and 2.0 × 10^?8 to 3.0 × 10^?6 g mL^?1 for yeast RNA (yRNA), and their detection limits are 2.5 × 10^?9 g mL^?1, 3.2 × 10^?9 g mL^?1 and 7.3 × 10^?9 g mL^?1, respectively. Samples were satisfactorily determined. And the system of Km-Al(III)-AgNPs was used as a fluorescence staining reagent for sensitive DNA detection by DNA pattern of agarose gel electrophoresis analysis. The results indicate that the fluorescence enhancement should be attributed to the formation of Km-Al(III)-AgNPs-nucleic acids aggregations through electrostatic attraction and adsorption bridging action of Al(III) and the surface-enhanced fluorescence effect of AgNPs.