Nanoparticle detection by microfluidic resistive pulse sensor with optical evidence

This paper reports a device that performs nanoparticle detection with a microfluidic differential Resistive Pulse Sensor (RPS). By 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 490nm on a microfluidic chip. An 8 mu m gate and a 2.7 mu m gate detected the 490 nm particle. The electrical signal was with optical evidence. The result showed 2.7 mu m chip can realize signal to noise ratio higher than 10. 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.