A versatile and smartphone-integrated detection platform based on Exo III-assisted recycling and DNAzyme amplification.

Staphylococcus aureus (S. aureus) is a widespread foodborne pathogen, causing a serious threat to human health and public safety. Thus, it is significant for rapid S. aureus determination. Herein, a visual and smartphone-integrated aptasensor for intact S. aureus was fabricated based on the Exo III-assisted recycling and hemin/G-quadruplex DNAzymes for signal amplification. Different concentrations of S. aureus caused the difference in releasing different amounts of DNAzymes via Exo III-assisted recycling reaction. These DNAzymes catalyzed the oxidation of 2,2′-azino-bis(3-ethylbenzothiozoline-6-sulfonic acid) (ABTS2-) to colored ABTS•−, which were respectively analyzed by smartphone and UV-Vis spectrophotometer for quantification. This assay exhibited good analytical performance with a detection limit of 32 CFU·mL−1 and a wide linear range. It also possesses the ability in complex sample matrices detection, low cost, and portability with the employment of a smartphone, making it a rapid, simple, and point-of-care test (POCT) method with great potential in food safety control. • A smartphone-integrated dual-readout aptasensor for Staphylococcus aureus was constructed. • This method showed a good analytical performance and met the POCT requirement for application in food safety control. • A versatile platform for simple and intact detection of biomolecules was developed. [ABSTRACT FROM AUTHOR]