A cell becomes a laser

Science : A laser built into a single cell may one day be used for light-based therapeutics, writes Jon Cartwright for Science. Physicists Malte Gather and Seok-Hyun Yun of Harvard Medical School used cells derived from a human kidney and added the DNA that codes for green fluorescent protein (GFP), then placed some of the cells producing GFP between two mirrors a single cell’s width apart. To lase, the GFP in the cells needed to be pumped with another laser, which sends pulses of blue light at about 1 nanojoule. The light bounced back and forth, amplifying the diffuse light from the GFP into a coherent green beam . Gather and Yun are interested in the therapeutic applications of their device. They also speculate that it might eventually help the backbone of optical communications shift to biotechnology.