Novel Readout Circuit for Memristive Biosensors in Cancer Detection

Abstract—We present a novel circuit for the automated and quick characterization of an array of experimental memristive nanowires that are functionalized as biosensors. Successfully functionalized nanowires will express the concentration of target molecules by hysteretic gaps of the zero crossing of their mem-ristive I/V characteristics as the voltage across them is swept up and down. The width of the voltage gap is directly proportional to the target molecule concentration. The characterization circuit sorts out faulty, i.e. non-conducting nanowires in the array, and performs an analog to digital conversion of the voltage gap to assess successful functionalization of the others, and thus significantly reduces the time for functional testing. Many of the test parameters are configurable: the speed and range of the voltage sweep and the resolution of the measurements. An initial prototype 2x2 array of the circuit has been layed out in 0.35µm CMOS technology within an area of 0.429 mm2 and has been thoroughly characterized in simulation, has been layed out, and is ready for fabrication. Index Terms—Memristive, bio-sensor, fully pinched current de-tection, femto amps, sub-hertz triangular voltage source, cancer detection I