Code-multiplexed sensor networks for microfluidic impedance spectroscopy

A microfluidic device for particle analysis, comprising:

• a plurality of microfluidic channels for the passage of a particle-laden fluid flow;
• a plurality of impedance sensors, each of the plurality of impedance sensors being dedicated to a single microfluidic channel for outputting a signal representative of an impedance across the corresponding microfluidic channel, each of the plurality of impedance sensors comprising a coded sequence of opposing electrode fingers, the coded sequences of the impedance sensors being distinct from one another;
• and
• a signal generator in signal communication with the impedance sensors for driving the impedance sensors with an excitation signal, the signal generator being configured to output a multi-frequency excitation signal comprising multiple concurrent tones to each impedance sensor, wherein
• the impedance sensors are configured in signal communication with the signal generator such that each impedance sensor is driven by the multi-frequency excitation signal with the multiple concurrent tones to generate a multi-frequency signal representative of impedance across the corresponding microfluidic channel, and to output the multi-frequency signals of the plurality of impedance sensors as a single multi-frequency multiplexed signal that comprises each of the multi-frequency signals generated by the individual impedance sensors, and
• the microfluidic device further comprises:
• first circuitry programmed to separate the multi-frequency multiplexed signal into multiple single-frequency multiplexed signals, with a separate single-frequency multiplexed signal corresponding to each tone of the multi-frequency excitation signal, and
• second circuitry programmed to separate each of the single-frequency multiplexed signals to extract single-frequency output signals corresponding to each of the impedance sensors.