PARTICLE FLOW SWITCH UTILIZING ULTRASONIC PARTICLE SWITCHING IN MICROFLUIDIC CHANNELS

摘要

This paper describes a method to switch suspended particles from one medium to another. The method combines an ultrasonic standing wave field with the laminar flow properties of a silicon micro channel. Suspended particles in a contaminated medium enter the channel through side inlets and a clean medium enters through a centre inlet, forming three laminated streams. Acoustic radiation forces subsequently drive the particles in the suspension into the middle of the channel thereby switching them from the contaminated medium to the clean. The channel is split into three exit channels separating the particles, now in the clean medium, from the contaminated fluid in the side outlets via the centre outlet. Experiments have shown that more than 90% of the contamination can be removed using this method.