We present an autonomous multiplex and multi-target nanomembrane sensor platform that can operate autonomously without any external control and can store the sensing records permanently. It is hence ideal for embedded and remote diagnostic applications. The sensing, control and memory elements are all nonlinear fluidic based ion circuits that can be immersed in any electrolyte medium. The nanomembranes are ion-selective membranes functionalized with oligo-probes whose nonlinear I-V curves exhibit an inflection point due to non-equilibrium ionic currents through the membrane [1,2]. The capture of charged targets produces a large shift in the current if the sensor is designed to operate at the inflection point. These nanomembrane sensors are fabricated directly into the fluidic resistive random-access memory (FRRAM) array with a non-volatile binary memory activated by a built-in fluidic logic circuit. Both the memory and logic circuits are composed of fluidic-based ion memristors as elementary bistable elements. They are enabled by a resistive-switching phenomenon between a silicon microelectrode and the aqueous medium, due to the electrochemical formation of an interfacial nanoscale oxide film on the silicon microelectrode under anodic polarization. Optimal impedance matching of the nonlinear resistive-switching memory to the I-V sensor features produces a 10 on/off ratio and a 1s short switching time. An ionic flip-flop latch with a specific operation protocol is then designed from this fluidic-based ion memristor to sample and digitize the ion current signal from each nanomembrane sensor within the array. Different sensing-memory cells for multiple nucleic acid targets are assembled by a crossbar architecture, to complete the multiplex nanomembrane sensor platform. Under this configuration, every sensing-memory cell in the array can be triggered to register its ion current signature, which greatly reduces the sensing assay time and operational complexity. All sensing results are stored in the FRRAM array as a non-volatile binary memory and can be retrieved days later. A prototype of this multiplex nanomembrane sensor platform will be presented.
1. Slouka Z, Senapati S, Chang HC. Microfluidic systems with ion-selective membranes. Annu Rev Anal Chem. 2014;7:317-35.
2. Senapati S, Slouka Z, Shah SS, et al. An ion-exchange nanomembrane sensor for detection of nucleic acids using a surface charge inversion phenomenon. Biosens Bioelectron. 2014;60:92-100.
See more of this Group/Topical: 2015 Annual Meeting of the AES Electrophoresis Society