Engineering of a DNAzyme-based aptasensor for highly efficient ATP detection and oyster freshness evaluation

Adenosine triphosphate (ATP) levels are recognized as a critical indicator of microbial content in food safety. The development of highly efficient ATP-sensing methods is essential for assessing food freshness. Herein, we propose a simple-yet-efficient hemin/G-quadruplex (G4) DNAzyme-based aptasensor for ATP detection and oyster freshness assessment. The anti-ATP aptamer subunits specifically bind to ATP, leading to self-assembly of the hemin/G4 DNAzyme. The newly produced DNAzyme then catalyzes the oxidation of ABTS 2- to produce the colored ABTS •− , providing an absorbance response for sensitive ATP analysis. The aptasensor facilitates high-performance and accurate determination of ATP with a low detection limit of 0.065   μM. Furthermore, this sensor enables reliable ATP analysis in oyster samples and evaluation of oyster freshness. In particular, a good linear correlation was established between microbial content and ATP levels. The proposed aptasensor for the assessment of freshness is characterized by its simplicity and efficiency, potentially offering a new tool to monitor food safety.