An application specific multi-channel stimulator for electrokinetically-driven microfluidic devices

This paper presents a sixteen-channel sinusoidal generator with independent control of frequency and amplitude for each channel. This generator has application as stimulator of microfluidic devices that use electrokinetic forces for particle manipulation. The stimulator is based on a CMOS application specific circuit and an interface card. Several generator techniques were compared based on frequency range, total harmonic distortion (THD), and on-chip required area. The selected approach is based in a triangle-to-sine converter and presents a frequency range of 8kHz to 21MHz, an output voltage range of 0V to 3.1V_PP, and a maximum THD of 5.11%. The device, fabricated in a 0.35μm CMOS technology, has a footprint of 1560μm×2030μm. Additional electronics in the interface card extends the frequency and voltage ranges to 50Hz-21MHz and 0-20V_PP. The generator functionality was tested by implementing an experimental set-up where particle trapping was performed. The experimental set-up consisted of a micromachined channel with embedded electrodes configured as two electrical ports located at different positions along the channel. By choosing specific amplitude and frequency values from the generator, different particles suspended in a fluid were simultaneously trapped at different ports. The multichannel stimulator presented here can be used in many other microfluidic experiments and devices focused on particle trapping, separation and characterization.