Fig. 7

a Schematic of SAW device (side view) and SAW-induced lysing of exosomes to release RNA for detection. SAWs generated at the transducer refract into the liquid bulk, inducing fluid motion, and electromechanical coupling also generates a complimentary electric wave at the surface of the substrate. b Schematic of ion-exchange nanomembrane sensor consisting of two reservoirs separated by the membrane. RNA in the sensing reservoir hybridize to complimentary oligos immobilized on the surface of the membrane. The inset shows the ion transport through the device to generate current and the right image is a characteristic current–voltage curve illustrating the under-limiting, limiting, and over-limiting regimes [38]