Dual microRNAs-driven enzyme biofuel cells: Visualization biosensing system with capacitor assistance output signal amplification

We present a dual-microRNAs-driven enzyme biofuel cells (EBFCs) based visual self-powered biosensing system with a capacitor assistance significant amplification of the output signal for the sensitive detection of microRNA-21 and microRNA-141. When microRNA-21 is captured by the aptamer (Atp1–21), the glucose oxidase (GOD)-modified aptamer (Atp2–21-GOD) is immobilized on the electrode surface by base-complementary pairing. When microRNA-21 and microRNA-141 are captured by the dual aptamer recognition system, the enzyme load is more effectively increased and the input voltage of the EBFCs is significantly enhanced. In the linear range of 0.0005–100 PM and 0.001–1000 PM, the detection limits for microRNA-21 and microRNA-141 are 0.16 and 0.36 fM, respectively. Furthermore, the EBFCs are connected to the capacitor integrated circuit, and the input voltage of the EBFCs is converted to an enhanced instantaneous current and charging to the capacitor which is then directly detected by a multimeter, and the sensitivity of sensing system is improved by 29.48 times. In order to improve the reproducibility and accuracy of self-powered biosensing system, the reading of the multimeter is obtained in real time by software that opens new door to the visualization of detection signal. The method provides an efficient strategy for visualization of multimeter-based detection signal and opens the possibility for medical diagnosis and therapeutic device power in the biosensing device.