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Scientists Have Created a Self-Contained Laser in a Cell

Pig skin illuminated by cellular lasers. Credit: Matjaž Humar and Seok Hyun Yun

Modern medicine is overflowing with futuristic concepts, but even so, the notion of embedding lasers into living cells is a whole new level of mind-boggling. But cellular microlasers are very much a reality, according to a paper published today in Nature Photonics, written by physicists Matjaž Humar and Seok-Hyun Yun of the Wellman Center for Photomedicine.

Yun was part of the team that introduced the first "living laser" back in 2011, which was created by hacking a cell with bioluminescent DNA, placing it between two mirrors, and blasting it with pulses of light. With this new paper, he and Humar have taken the technology a step farther by creating a self-contained cellular laser.


Lipid droplets in yellow, cell nuclei in blue. Credit: Matjaž Humar and Seok Hyun Yun

Instead of inducing cells to lase with external mirrors, this time the team has implanted "mirrors" in the form of oil droplets and polystyrene beads inside cells. These droplets are tiny, measuring less than the width of a human hair, and they are packed with different dye colors and configurations. When excited by outside sources of light, they can be induced to shine over a number of different wavelengths, like a laser light show inside a living organism.

You might be asking why scientists want to shoot colorful lasers out of cells in the first place, and you would be right to ponder this improbable question. For starters, this technique allows scientists to literally illuminate the complex mechanics of cellular function in pristine detail.

"Right now, the technology is ready for applications in laboratory settings—to study cells and later to study their uses in small animals," Yun told me over email. "For example, [we use] the lasers to understand how cells move and respond to external force."

Video explainer of self-contained cellular microlaser. Credit: YouTube/Research Square

But as evidenced by the many teams working on living lasers, the applications for this technology go far beyond cellular research. "The general concept of using biological materials, living matter, and cells to build photonic devices have begun to be widely accepted in the community," Yun said. "Several groups have demonstrated various types of lasers made of biological materials."

One of the main areas of interest for these teams is the development of biodegradable microlasers capable of autonomously tagging individual cells, either for study or treatment.

"Injecting or implanting 'biological lasers' that are biocompatible and small enough—like the cell lasers shown in this work—for treatment of disease and diagnosis is one direction of our research," Yun said, though he noted that "it will take some time and effort to demonstrate the potential in a clinically relevant setting."

Laser droplets in green. Credit: Matjaž Humar and Seok Hyun Yun

Regardless, the idea that our future visits to the doctor might entail the ingestion of tiny lasers that color-code cells is surely enough mental cud for the moment. Yun and Humar have upped the stakes on living laser research with this latest paper, and it will be fascinating to see where this fledgling field heads next.