Floating ‘vacuum’ probes cell behavior

MCGILL U. (CAN) — New technology is expected to serve as a powerful tool to study crucial cellular processes, including cancer cell formation and how neurons align themselves in the developing brain.

The device could be compared to a microscopic jet vacuum cleaner—about the size of a pen nib—that hovers over cell surfaces without ever touching them. The technology is based on using quadrupoles—or paired identical objects—two “positive” and two “negative” arranged in a square in order to create a force field between them.

Researchers detail the work in an article published in the journal Nature Communications.


Electrostatic quadrupoles are used in radio antennae, and magnetic quadrupoles focus beams of charged particles in particle accelerators.

Quadrupoles that also exist in fluids have been described theoretically for decades, but this is the first time they have been fabricated in a lab setting, according to developers Mohammad Ameen Qasaimeh and David Juncker from the department of biomedical engineering at McGill University and Thomas Gervais from the Ecole Polytechnique of Montreal.

The device is fabricated by etching four holes in a silicon tip, which is about 1 mm square. When the device is brought close to a surface, it behaves like a water jet vacuum cleaner.

Two apertures—the “plus” holes, or sources—emit microscopic jets of fluid onto the surface below and the two other apertures—the “minus” holes, or drains—immediately suck them back into the device.

In the vacuum cleaner analogy, the carpet is replaced by a slice of living tissue, or a layer of adherent cells, and the device floats over the surface to reach a desired target. It then simply sends out a stream of fluid with the chemicals needed to stimulate, probe, detach, or kill the cells, depending on the application.

The device also can create regions of smoothly varying chemical concentration called gradients that are key to studying a variety of cellular processes, including how bacteria and other cells move about in the body.

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