No abstract

In this paper, we report on a flexural plate wave device (FPW) for particle entrapment inside a microfluidic channel. Surface micromachined polysilicon actuators placed inside the channel are driven at their flexural plate wave resonances by applying suitable drive-voltage to an external bulk piezoelectric PZT (Lead-Zirconate-Titanate Oxide) plate. The resonating polysilicon surface micromachines generate shear viscous acoustic field in the surrounding fluid. The field results in fluid vortices that can trap particles in the fluid flow. The acoustic vortex generator can be used for bead concentration in micro-fluidic assay.

No abstract

In this paper, we report on a novel 'particle capturing' MEMS device for microfluid sample collection. When the resonance modes of the center-anchored surface micromachined polysilicon disk actuator inside the fluid channel are excited, time averaged acoustic force generates pressure gradients along the disk periphery. These pressure gradients are used to obtain fluid vortices by optimum design of poly-disk substrate gap and channel height. The vortices trap particles traveling in the channel due to pressure driven flow. In many ways this vortex capture device is biomimetic -it is like the single-celled organism called Vorticella, which collects food by inducing local vortices [1]. This particle concentrator paradigm gives us the tight control of the particlc capture location so that wc can integrate optical or acoustic sensors to measure the change in captured particle density over time.

No abstract