Amplitude modulated micro Coulter counter for high throughput counting of microparticles

We present the design, fabrication and testing of a multiplexed multichannel Coulter counter. The micromachined device is used to achieve high throughput for counting microparticles. Multiplexed detection is achieved by amplitude modulation of signals from individual channels, requiring only one set of detection electronics. Preliminary testing results using 30 mum polystyrene particles demonstrate the feasibility of the multiplexed detection principle using both single and multiple channel sensors. The multiplexed detection principle can be extended to a larger number of channels to further improve the throughput.