Researchers at Penn State are using lithography and polydimethylsiloxane (PDMS)-glass to fabricate a device that manipulates microparticles using pressure waves. As an example of its applications, the device can be used to manipulate single cells and assemble them in certain patterns for more efficient drug tests. Professor Tony Huang from Penn State and his team’s project made the cover of the journal Lab on Chip.
In the paper, they detail the fabrication method and the workings of the device. The group was able to develop reusable multi-layered acoustic tweezers by using standing surface acoustic waves transmitted to a disposable layer made of PDMS-glass. The other layer of the device is a lithium niobate piezoelectric material that is coated with paralleled interdigital transducers that is coupled to the PDMS-glass by a thin layer of gel. When the standing waves are sent through the piezoelectric substrate, pressure nodes form between the transducers which then transmit the waves to the microfluidic device layer. Depending on how the user manipulates the standing waves to have specific displacement nodes, the cells or particles that need to be moved can be patterned and transported into various different configurations.
In a previous iteration of the device, the researchers had the microfluidic channel permanently bound to the substrate and the ultrasound was sent straight into the fluid. With the new changes, this device becomes more convenient and closer towards commercialization. Dr. Huang believes that the disposable part of the device can be manufactured at around 25 cents per piece and the cost for electronics integrated with the permanent reusable layer would be a couple dollars.
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