Fluorescence enhancement effect of morin-nucleic acid-l-cysteine-capped nano-ZnS system and the determination of nucleic acid

Abstract

It is found that L-cysteine-capped nano-ZnS can further enhance the fluorescence intensity of the morin–nucleic acid system. Under optimum conditions, the enhanced intensity of fluorescence is proportional to the concentration of nucleic acid in the range of 7.0 × 10⁻⁸–1.0 × 10⁻⁵ g mL⁻¹ for fish sperm DNA (fsDNA) and 9.0 × 10⁻⁸–5.0 × 10⁻⁶ g mL⁻¹ for yeast RNA (yRNA). The corresponding detection limits (S/N = 3) are 2.0 × 10⁻⁸ g mL⁻¹ and 4.0 × 10⁻⁸ g mL⁻¹, respectively. The interaction mechanisms of morin–nucleic acid–L-cysteine-capped nano-ZnS system are studied by multiple techniques. It is considered that there exists synergistic effects of groove binding and electrostatic interaction between morin, L-cysteine-capped nano-ZnS and nucleic acid, and the complex of morin–L-cysteine-capped nano-ZnS-nucleic acid is formed.