A dual-locked DNA biosensor based on entropy drive circuit/ hybridization chain reaction cascade amplification for AND logic detection of APE1 and miR-21.

Accurate identification of cancer cells is crucial for early cancer diagnosis and treatment. However, most current methods targeting a single analyte are insufficient for the precise recognition of cancer cells. Herein, we propose a cascade amplification sensing strategy based on a dual-locked DNA probe for the simultaneous detection of two breast cancer biomarkers: microRNA-21 (miR-21) and apurinic/apyrimidinic endonuclease 1 (APE1). This strategy utilizes a stringent dual-lock logic control mechanism to activate the cascade amplification of entropy driven catalysis and hybridization chain reaction only when both targets are present simultaneously. This novel design effectively suppresses the background noise and significantly enhancing detection specificity and reliability. It enables the detection of miR-21 with a linear range of 0.2-10 nM and a limit of detection (LOD) of 74 pM, as well as the detection of APE1 with a linear range of 0.3-4.0 U/mL and a LOD of 0.11 U/mL. The biosensor effectively distinguishes breast cancer cells from normal mammary epithelial cells, offering a novel approach for biological research and cancer cell identification.