Study on the interaction between silver nanoparticles and nucleic acids in the presence of cetyltrimethylammonium bromide and its analytical application

A novel method is proposed in this paper, that is the silver nanoparticle (nanoAg)–cetyltrimethylammonium bromide (CTMAB) is used as the probe of resonance light scattering (RLS) for the determination of nucleic acids. Under optimum conditions, there are linear relationships between the quenching extent of RLS and the concentration of nucleic acids in the range of 4.0 × 10−9–2.0 × 10−6 g mL−1 for fish sperm DNA (fsDNA), 7.0 × 10−9–1.8 × 10−6 g mL−1 for calf thymus DNA (ctDNA) and 6.0 × 10−9–1.0 × 10−6 g mL−1 for yeast RNA (yRNA). The detection limits (S/N = 3) of fsDNA, ctDNA and yRNA are 2.7 × 10−10 g mL−1, 4.8 × 10−10 g mL−1 and 7.2 × 10−10 g mL−1, respectively. The studies indicate that there are interactions among nanoAg, CTMAB and fsDNA through electrostatic and chemical affinity, and the nanoAg–CTMAB complex can induce the structural change of base stacking and helicity of fsDNA.