New Tweezing System Uses Optical Phased Arrays for Better Performance

MIT researchers have created a miniature, chip-based trapping and tweezing system that can manipulate biological particles using light, similar to a "tractor beam" from science fiction. This innovation could potentially transform how biologists and clinicians study DNA, classify cells, and investigate disease mechanisms.

The palm-sized device employs a beam of light emitted by a silicon-photonics chip to manipulate particles millimeters away from the chip surface. Unlike traditional optical tweezers that require bulky microscope setups, this chip-based solution offers a more compact and accessible approach for optical manipulation in biological experiments.

A key advantage of this new technology is its ability to penetrate glass cover slips protecting biological samples, allowing cells to remain in a sterile environment during manipulation. This overcomes a significant limitation of previous chip-based optical tweezers, which could only capture particles very close to the chip surface, risking contamination and cell stress.

The MIT team achieved this breakthrough using an integrated optical phased array, a system of microscale antennas fabricated on the chip. By electronically controlling each antenna's optical signal, they can shape and steer the light beam, focusing it about 5 millimeters above the chip's surface.

"No one had created silicon-photonics-based optical tweezers capable of trapping microparticles over a millimeter-scale distance before," says Jelena Notaros, senior author on the paper published in Nature Communications.

The researchers successfully demonstrated their device by capturing and manipulating polystyrene spheres and cancer cells. They hope to further refine the system to allow adjustable focal height and explore more complex manipulations of biological particles using multiple trap sites simultaneously.