Real-time multiple signal amplification self-powered biosensing platform for ultrasensitive detection of MicroRNA

A real-time self-powered biosensor is designed for ultrasensitive detection of microRNA-21 based on electro-chemical energy device capacitor and target-induced recycling double amplification strategy, which greatly improves the output signal by converting a small number of targets into two glucose oxidase labeled output strand DNAs, and the squeezed-out output strand is recycled by the cathode to fix more signal [Ru(NH3)6]3+ to further improve the detection signal. A digital multimeter (DMM) is connected to computer for real-time dis-playing the output signal of the self-powered biosensing system, which improves the accuracy of the sensing platform. The sensitivity of the proposed biosensor is 116.15 mu A/pM for target microRNA-21, which is 32.26 times higher than that of pure EBFC (3.6 mu A/pM). The target concentration is proportional to the open-circuit voltage value in a wide linear range of 0.1-10000 fM with a low detection limit of 0.04 fM (S/N = 3). The method shows high sensitivity and excellent selectivity, and can be applied to detect tumor marker microRNA-21 in biological matrix.