Making Pig Fat into a Laser

Researchers have made pig-skin lasers. Yes, pig laser beams.

The technology, outlined in a paper published today in Nature Photonics, showed that pumping light into fat cells could turn them into tiny, self-contained lasers.

The microlaser technique could afford scientists new ways to study and use cells, but mostly it’s just “very cool,” says Russ Algar, an assistant professor at the University of British Columbia in Vancouver, Canada, who wasn’t involved in the work.

The team at Harvard University turning cells into lasers has tried it before. But last time they had to put the cells inside a special optical cavity to make them shine (see “Lasers Made from Human Cells”). Pumping light into a sphere can create the resonance that produces sharply defined laser light.

This time the team showed that some cells could lase on their own. They chose pig fat because each cell contains a large, nearly perfectly spherical ball of fat inside it. They added a glowing fluorescent dye and then started up the microlasers by shining in light through an optical fiber.

Seok Hyun Yun, the paper’s senior author and an associate professor at Massachusetts General Hospital and Harvard Medical School, says his long-term goal is to use intracellular microlasers as research tools, sensors, or perhaps as part of a drug treatment. Lasing cells could add to the repertoire of techniques that scientists have to label and study cells like adding quantum dots or bioluminescent particles. For instance, the laser light put out by a sphere inside a cell will change depending on how much pressure a cell is under.

It’s not just pig fat lasers, by the way. Yun’s team also found they could turn others cells into a laser by injecting oil droplets into them. They also tried inserting tiny polystyrene beads to change the tuning of the laser. By combining beads of different sizes with several fluorescent dyes, the researchers estimated they should be able to create roughly as many unique laser tags as there are cells in the human body.

Xudong Fan, a professor of biomedical engineering at the University of Michigan, who wasn’t involved in the study either, says he sees some potential in being able to study cells as they interact via biolasers. For his part, Algar says he doesn’t see much practical use for the technology. But who knows. The payoff, he says, is more the “I didn’t know that was possible” factor.