Research on rapid detection of Staphylococcus aureus by fluorescent biosensor based on DNAzyme

Objective To solve the problems of time-consuming and complex operation in traditional methods of detecting Staphylococcus aureus, a fluorescent biosensor based on deoxyribonuclease (DNAzyme) was developed to achieve rapid detection of S. aureus.

Method The fluorescence biosensor was made by combining DNAzyme with specific complementary chain substrate, and optimized for the concentration of biomaterials and pH of solution. Then, the specific detection of five different bacteria such as S. aureus, Escherichia coli, Bacillus, Streptococcus agalactiae and Proteus was performed. Finally, the DNAzyme-based fluorescent biosensor was tested and verified on milk samples.

Result The fluorescent biosensor based on DNAzyme can detect S. aureus within 3 min at a pH of 6.8, with a linear range of 1−1×10⁷ cfu·mL⁻¹ and a minimum detection limit of 1 cfu·mL⁻¹.

Conclusion The fluorescent biosensor based on DNAzyme solves the problems of time-consuming and complex operation of traditional detection methods, and realizes the rapid detection of S. aureus in milk, which has significant practical value.