How about this for a bright idea: turn individual human cells into functioning lasers that emit light when they’re excited.
As New Scientist reports, the Harvard team has demonstrated that particles and droplets in skin can be exploited to emit light. In one example, they injected tiny oil droplets, later filled with fluorescent dye, into human cells; when a light pulse hit the droplet, the dye atoms emitted light in a tightly focused beam. In a second example, 10-micron polystyrene beads were ingested by cells known as macrophages (a type of white blood cell) and ultimately served the same purpose as the oil drops.
And in a final example, the team even managed to show that existing fatty droplets inside cells could be used to the same ends. In pig skin (though the same technique should work in human skin) light injected into the skin caused fatty cells tagged with a fluorescent dye to emit laser light in just the same way. “We are all made of lasers,” said Matjaž Humar, one of the researchers, to New Scientist. The results are published in Nature Photonics and Nano Letters.
While the work may seem frivolous, the researchers reckon that the techniques could be used to track and monitor tumour cells, perhaps even giving different types of cells different laser signatures. [Nature Photonics and Nano Letters via New Scientist]