Pew pew pew: Human cells converted into mini lasers

Scientists at Harvard Medical School have found a way to take living human cells and transform them into tiny lasers that can emit light to track diseases such as cancer, according to research published earlier this week in the journal Nature Photonics.

In fact, Matjaz Humar and Seok Hyun Yun of the Wellman Center for Photomedicine not only accomplished the feat, but according to Gizmodo and Discovery News, they came up with three different ways to make these light-emitting, disease-tracking mini-lasers from human cells.

In one technique, they injected tiny oil droplets into cells, creating a cavity that could be filled with fluorescent dye. When an external pulse of light was directed at the droplet, the cells gave off a narrow beam of light. In another, tiny polystyrene beads were ingested by a type of white blood cells called a macrophage and used to perform functions similar to the oil droplets.

Fatty deposits already in the cell were used to emit beams of light in the third technique. In pig skin, light injected into the skin caused fatty cells tagged with fluorescent dye to emit laser light in a way similar to the first two techniques, and the researchers believe that the method should be able to work in human skin as well.

Potential new way to track cells, treat illnesses

Currently, fluorescent dyes are often used to tag living cells and emit light. However, since they produce light in a wide range of wavelengths, it can be difficult to tell different types of tagged cells apart. The new techniques turn cells themselves into tiny lasers and could make it much easier to tell tagged cells apart, since lasers have a far narrower range of wavelengths.

“Our new cell laser technology will help us understand cellular processes and improve medical diagnosis and therapies,” Yun and Humar wrote in a piece for “They could eventually provide remote sensing inside the human body without the need for sample collection.”

“A cell is a smart machine, equipped with a computer with ‘DNA Inside,’” the authors added. “Specialized cells, such as immune cells, can find the disease and site of inflammation, carrying the laser to the target for laser-based diagnosis and therapies. Imagine rather than a biopsy for a lump that doctors suspect to be cancer, cell lasers helping determine what it’s made of.”

In addition, they explain that cell lasers could eventually be used to deliver therapies, such as through a method to activate photosensitive drugs that target and eliminate microbial pathogens or cancer cells. They also believe that scientists could eventually give each cell in the human body unique laser signatures, making it easier to track tumor cells or monitor how cells respond to inflammation.

(Image credit: Matjaž Humar and Seok Hyun Yun)