Nanoparticle detection by microfluidic Resistive Pulse Sensor with a submicron sensing gate and dual detecting channels-two stage differential amplifier

This paper reports a method of detecting nanoparticles using a microfluidic differential Resistive Pulse Sensor (RPS). Using a single microfluidic channel with two detecting arm channels placed at the two ends of the sensing section, the microfluidic differential RPS can achieve a high sensitivity allowing the detection of nanometer size particles. Two-stage differential amplification is used to further increase the signal-to-noise ratio. This method is able to detect nanoparticles of 490 nm and 220 nm on a microfluidic chip. The method described in this paper is simple and can be applied to develop a compact device without the need of bulky, sophisticated electronic instruments or complicated nano-fabrication processes.