Ultrasensitive micro/nanoscale resistive pulse sensors by integrating fluidic devices with MOSFETS

Nanofluidic sensors have been developed over the past decade and demonstrated the capability of sensing single DNA molecules. One class of nanofluidic devices is based on the resistive pulse sensing technique and a modulation of the baseline ionic current can be observed when molecules are translocated through the sensing nanopore or nanochannel. In this scheme, the ionic current modulation is approximately the same as the channel resistance modulation, requiring the channel size be comparable to the molecules to be detected. In this paper, we present a new sensing scheme to detect the translocation of particles through a fluidic channel, which amplifies the resistance modulation by 40-80 times. The device connects the gate of a MOSFET with a fluidic circuit and monitors the drain current modulation of the MOSFET to detect particles, instead of directly monitoring the ionic current through the fluidic channel. The minimum volume ratio detected is 0.006%, about ten times smaller than the lowest detectable volume ratio reported in the literature by using the resistive pulse sensing technique. Although at current stage the device is only fabricated at microscale level, we envision that the same scheme can be applied in nanofluidic devices for single molecule detection.