MIT researchers have developed a miniature, chip-based “tractor beam” that could transform the way biologists and clinicians study DNA, classify cells, and investigate disease mechanisms. This innovative technology uses a beam of light emitted by a silicon photonics chip to manipulate particles from a distance, offering a more compact, accessible, and high-throughput solution for optical manipulation in biological experiments. The key breakthrough is the ability to trap and tweeze cells more than a hundred times further away from the chip surface, enabling experiments in sterile environments without contaminating the chip. This technology has the potential to “democratize” optical tweezing experiments and improve the sensitivity of disease diagnostics. Optical Tweezers, Silicon Photonics
Harnessing the Power of Light
Since their invention in the 1970s, optical traps, and tweezers have been widely used within biology to capture and manipulate small particles using focused beams of light. But for the most part, these conventional designs have suffered from their bulky form and requirement of multiple dedicated devices to steer light around. This is where the MIT researchers’ breakthrough comes in.
The team has developed a compact tractor beam enabled by this technology in a centimeter-sized silicon photonic chip, that can move and manipulate particles remotely to attract the particles toward the waveguide by manually tuning individual phase shifts based on AI feedback. In doing so, the breakthrough not only makes it more affordable and scalable, but also solves a bigger problem: the challenge to trap and tweeze cells meters above the surface of a chip — far enough away from the chip’s surface which would prevent contaminating the sample or killing off cells.
Getting past the limits of chip-based optical trapping
The trouble was, in previous versions of chip-based optical tweezers, the particles could only be trapped a few hundred nanometers away from the surface of the chip – a large problem for biologists with cells sealed between two clean glass coverslips. The MIT researchers were able to address this problem by fashioning a chip-based device that they call an integrated optical phased array. The researchers shaped and steered the light beam by controlling optical signals from each antenna, focusing the light up to 5 millimeters above the chip surface.
This is the discovery that hyperactive filed science and other proponents of safe-freezing have been waiting for a way to keep protected biological samples inside their clean setups in “safe storage” while still allowing them to be “played with”. By trapping and tweezing both polystyrene spheres and cancer cells, the researchers showed that it is indeed capable of successfully grabbing particles which means there are plenty of applications in the life sciences.
OPTeon: Democratizing Optical Tweezing experiments
Perhaps most interestingly, this technology could democratize optical tweezing to a greater part of the research community. Until now, though, traditional optical tweezers have required expensive equipment in a carefully equipped lab — while the MIT system developed for this research is much smaller and costs just a fraction of what another setup could.
Or as University of Rochester professor Ben Miller, lauds: “These new tools are going to help us probe basic problems in single-cell biophysics that previously only a handful of labs could’ve dug into.” The ability to democratize optical manipulation could unlock transformative findings and characterizations of biological processes, disease machinations, and diagnosis. The team of researchers is now looking at ways to make the system even more precise, including the possibility of having adjustable focal heights and using multiple trap sites to make this new technology even more powerful than it already is.
