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Tiny tweezers can grip little critters using sound waves alone

Acoustic tweezers capable of capturing and moving single cells are compared to a U.S. dime.Xiaoyun Ding, Stephen J. Benkovic, Tony Jun Huang / Penn State

Ultrasound, the same technology used to peer inside a mother’s womb to view a developing fetus, has been harnessed to non-invasively grip and move a millimeter-long roundworm.

The acoustic tweezers are about the size of a dime. The device is based on a piezoelectric material that converts vibrations into standing surface acoustic waves called SAWS.

The SAWs create pressure fields in the liquid medium that hold the specimen, according to Pennsylvania State University, where the technology was developed by bioengineer Tony Jun Huang and colleagues.

The electronics in the device can tune the SAWs to precisely and noninvasively hold and move the specimen, the university explained.

The researchers add that the technology is much cheaper than optical tweezers that use lasers to manipulate particles. What’s more, the acoustic tweezers don’t build up cell-damaging heat like their optical cousins. 

As a proof-of-concept, the acoustic tweezers were used to spell out PNAS and PSU with roundworms.Xiaoyun Ding, Stephen J. Benkovic, and Tony Jun Huang / Penn State

As a result, the acoustic technology can be used to mimic the conditions inside the body where cells are subject to waves of pressure and pulses of chemicals, the university said. This can, for example, allow researchers to study the effect of drug pulses on a cell’s biochemistry.

To prove the tweezers work, Huang’s team used them to spell PNAS and PSU in petri dishes with the roundworm Caenorhabditis elegans, which serves as a model organism for biological research.

A paper on the tweezers appears in the journal Proceedings of the National Academy of Sciences (PNAS). PSU is the acronym for Pennsylvania State University.

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