An array of “cogwheel-shaped” optoelectronic microrobots developed at the University of Toronto can scoop up and transport individual cells. Credit: Shuailong Zhang, University of Toronto.

Not Just Another Cog in the Machine

These tiny, cogwheel-shaped microrobots can scoop up and move individual cells in a tissue while being guided by light.


Can a single cogwheel be an entire robot? These simple and tiny one-piece machines can easily be controlled using light, scooping up and moving individual cells in a tissue.

The technology was developed by University of Toronto co-authors Cindi Morshead, Aaron Wheeler, and Peter Zandstra (now at the University of British Columbia). Their study was published in the Proceedings of the National Academy of Sciences (PNAS).

Their microrobots make use of optical tweezers: controlled light patterns that trap small particles using the force exerted by light. Optical tweezers are precise and so widely used in biology that their inventor shared the 2018 Nobel Prize in Physics, but mammalian cells are fragile and their direct manipulation is slow and tedious.

By contrast, these specially designed cogwheels can be easily repositioned by using patterns of light to influence the electric fields around them. Every second they can be moved up to half a millimeter along any axis, or rotated all the way around. They feature a small opening and a circular central chamber to capture, transport, and deliver sub-millimeter payloads.

Cogwheel-shaped microrobots can be used to load, transport, and deliver cells using projected light patterns. Credit: University of Toronto.

The technique can be used to isolate single cells or microtissues, manipulate microscopic volumes inside closed systems, and influence cell-cell interactions. And all of this can be done using commercially available microscopes and consumer-grade optical projectors.

With greater speeds and less damage to target cells, these microrobots have the potential to enhance single-cell biology and give precise control over complex cellular microenvironments. They could also be used in a wide range of applications where miniaturization could be a benefit.

Accessing these tiny scales sets up these microrobots to make big moves in science.

‹ Previous post
Next post ›

Karyn Ho is a science animator and engineer who thrives at the interface between science, engineering, medicine, and art. She earned her MScBMC (biomedical communications) and PhD (chemical engineering and biomedical engineering) at the University of Toronto. Karyn is passionate about using cutting edge discoveries to create dynamic stories as a way of supporting innovation, collaboration, education, and informed decision making. By translating knowledge into narratives, her vision is to captivate people, spark their curiosity, and motivate them to share what they learned.