Researchers at Massachusetts General Hospital managed to harness a mammalian cell that expresses green fluorescent protein (GFP) to produce laser light. Though the setup involved two closely spaced mirrors, the cell itself produced, amplified, and helped focus light into nano-second long laser pulses. Practical applications of this unexpected technology are yet to be discovered, but the researchers believe that useful information contained within the laser light may lead to new ways to analyze various characteristics of different cells.
To determine the protein’s potential for generating laser light, the researcher first assembled a device consisting of an inch-long cylinder, with mirrors at each end, filled with a solution of GFP in water. After first confirming that the GFP solution could amplify input energy into brief pulses of laser light, the researchers estimated the concentration of GFP required to produce the laser effect.
Using that information, their next step was to develop a line of mammalian cells expressing GFP at the required levels. The cellular laser was assembled by placing a single GFP-expressing cell – with a diameter of from 15 to 20 millionths of a meter – in a microcavity consisting of two highly reflective mirrors spaced 20 millionths of a meter apart. Not only did the cell-based device produce pulses of laser light as in the GFP solution experiment, the researchers also found that the spherical shape of the cell itself acted as a lens, refocusing the light and inducing emission of laser light at lower energy levels than required for the solution-based device. The cells used in the device survived the lasing process and were able to continue producing hundreds of pulses of laser light.
Press release: Single GFP-expressing cell is basis of living laser device …
Abstract in Nature Photonics: Single-cell biological lasers