Acoustic Tweezers for those Pesky Little CellsCategory: Science & Technology
Posted: July 9, 2012 09:43AM
To study something it always helps to have a firm grasp on it, but that is not very easy when working with cells are small parasites. At such small sizes, physically holding the object could actually damage it, making it impossible to effectively study it. Optical tweezers have existed for a while now as a means to safely hold cells in a trap, without damaging them, but these devices have some limitations, so Penn State researchers developed Acoustic Tweezers that use sound instead of light to hold objects.
Transducers attached to a piezoelectric substrate are used to produce the ultrasonic waves needed for operation. The waves from the four transducers are carefully tuned to be standing acoustic waves. This keeps the resulting waves in the liquid medium around the specimen effectively still, with certain areas of high pressure and low pressure. Careful adjustments to the frequency of the sound allow the researchers to precisely move the specimen, whether it be a single cell or a C. elegans roundworm.
For the time being, optical tweezers will still reign for nanoscale objects, as the acoustic tweezers would need to reach much higher frequencies to trap such small particles. For these larger organisms though, acoustic tweezers may be the tool of choice as they require 10,000,000 times lower power densities and can work with tens of thousands of cells at a time.