Physicists maneuver DNA molecules using electrical fields, offering real-time control

Researchers in McGill’s Department of Physics have developed a new device that can trap and study DNA molecules without touching or damaging them. The device, which uses carefully tuned electric fields, offers scientists unprecedented control over how DNA behaves in real time, creating the opportunity for faster, more precise molecular analysis that could improve diagnostics, genome mapping and the study of disease-related molecules.

Doctoral student Matheus Azevedo Silva Pessôa, a nanofluids researcher, developed the tool in collaboration with his fellow students in Professor Walter Reisner’s Nanobiophysics lab. Researchers from Professor Sara Mahshid’s Bioengineering lab at McGill, genomics technology startup Dimension Genomics, and the University of California, Santa Barbara also contributed.

The paper, “Single-molecule capture, release, and dynamical manipulation via reversible electrokinetic confinement (RECON),” is published in Science Advances.

Harnessing DNA’s electric charge

“Previous models required you to mechanically control molecules to trap them,” Pessôa explained. “You have to confine the molecules in a groove so you can study them, and then mechanically induce a plate, or lid, to push the molecules inside a well. But sometimes they break, and the control over the position of these molecules is extremely limited.”

Now, researchers can more quickly and gently modulate each DNA molecule by harnessing its inherent electrical qualities to guide it into a small well.

Like tuning an AM radio dial

While previous research has attempted to control molecules with electric fields, the high voltage often caused various issues that made that approach impractical.

Pessôa said the new device lets researchers adjust the electrical voltage to a specific frequency, like tuning an AM radio dial. This fine control allows them to trap DNA molecules without damaging them.

Scientists can also release the molecules at will. By controlling how tightly the DNA is confined, they can observe its behavior in real time.

“This way, we can see the specific dynamics of the DNA, because we can confine the molecules for as long as we want without breaking them, and see what happens when the electrical field we use to trap them is changed,” he added.

The researchers say that manipulating DNA at such a small scale can also help accelerate chemical reactions such as triggering liposomes—fat-based carriers often used in drug delivery—to open and release their contents, allowing scientists to further study these dynamics.

The platform could also be used to simulate cell environments, making it a powerful tool for both diagnostics and discovery.

The researcher is among those listed as inventors on Dimension Genomics’s provisional patent application for this device.