High speed particles separation using ultrasound for microTAS and lab-on-a-chip application

Engineers have long envisioned that a handheld portable blood diagnosis device would be able to give an accurate measurement of chemical content based on a very small sample in the shortest time possible. One of the immediate applications of such device is the point of care (POC) diagnosis system, whereby a single drop of human blood would determine his health status. However, a major technical challenge lies in the ability to separate different particles, which in the case of human blood, is to separate red and white blood cells and plasma in a quick, cheap, reliable device with low power consumption. In this paper, we present some preliminary results from our tests of ultrasound standing waves as a potential separation mechanism for blood cells. Also, we report on the study of the behavior of suspended particles of the size equivalent to a human cell under the influence of ultrasonic acoustic field, using micro particle image velocimetry (PIV) measurement technique. This provides the fundamental understanding and foundation of designing an integrated microchannel structure that can provide ultrasonic cell separation in the microscale regime. The study has shown promising results of successfully separating two different particles based on their sizes difference.