Fig. 4: Detection mechanism.
From: Ultrasensitive rapid cytokine sensors based on asymmetric geometry two-dimensional MoS2 diodes
a Illustration of the folding of an aptamer, forming a compact G-quadruplex structure, due to the interaction of the TNF-α cytokine and aptamer, which brings negative charges closer to the Al2O3 thin film coated sensor surface. b Schematic diagram of a setup to support the proposed detection mechanism by investigating the effect of gate voltage on I–V response of a liquid-gate, asymmetric-geometry, diode sensor. c Drain-source current (IDS) versus drain-source voltage (VDS) for different applied gate voltages (VGS) ranging from 0 to −1 V with an increment of −0.1 V steps (the gate voltage was applied via a pure PBS drop as shown in Fig. 4b). d RFN versus VGS of the liquid gated sensor.
