An ultra-sensitive dual-signal ratiometric electrochemical aptasensor based on functionalized MOFs for detection of...

The dual-signal radiometric sensor can effectively reduce the difference between repeated detection and achieve higher accuracy, sensitivity and repeatability detection. In this work, we constructed a simple ratiometric electrochemical aptasensor based on functionalized ZIF-67 and ZIF-90 for sensitive detection of human epidermal growth factor receptor-2 (HER2). ZIF-67@Ferrocene (Fc)/antimonate nano flakes (AMNFs) as the capture probe has a large specific surface area and good conductivity, and have a strong adsorption capacity for aptamer single-stranded deoxyribonucleic acid (ssDNA). When the biomarker - HER2 interacts with aptamer ssDNA, it is easily desorbed from its surface. At the same time, ZIF-90@ methylene blue (MB) as the signal probe realizes one-step encapsulation of MB signal, which can avoid interference from external environment. When the target-HER2 exists, it is recognized by the capture probe, which leads to the decrease of the conductivity of the electrode. Under the action of the signal probe, the conductivity of the signal is recovered and the detection signal is amplified significantly. The designed ratiometric electrochemical aptasensor showed a wide linear range (0.5-1000 pg mL^-1) and a low detection limit (155 fg mL^-1) for HER2. Subsequently, it was applied to actual serum samples and showed acceptable applicability. It shows great potential for clinical screening and immediate detection of cancer biomarkers.