Recent work by Seok Hyun Yun and Matjaž Humar has shown us that laser shows aren’t just for Pink Floyd fans. These crafty researchers incorporated specific structures into individual cells, turning them into self-contained “microlasers”.
In its simplest form, laser (or light amplification by stimulated emission of radiation) technology uses an energy source to amplify photons bouncing between reflective surfaces, creating a narrow, very strong beam of light at a very specific wavelength. In this new breakthrough, the researchers used spherical structures small enough to fit inside cells as the amplification device.
Initial experiments used intracellular oil droplets or the lipid droplets stored within the body’s fat cells as the reflective surface to amplify light. In this case, the researchers used the properties of the emitted microlaser light to assess dynamic fluctuations in intracellular pressure at a single cell level – different pressures alter droplet shape and this in turn alters the light emitted by microlasers.
Substituting solid microbeads of varying forms for the oil/lipid droplets then enabled each cell to have its own distinct microlaser. Each bead, with its own specific size and shape, can generate laser light with narrow distinct parameters which can be used to identify and label that cell. Currently, overlap from different fluorescent dyes and background interference hamper conventional cell labeling, but this new technology, in theory, could individually tag every cell in the human body – that’s a jaw-dropping trillion cells!
Labeling cells using microlasers will realistically allow us to track thousands of cells within a single experiment, but the future applications of microlasers are even more fascinating. They can be further applied to measure cell movement and reaction to forces but also may be used to control photoactivatable gene expression or the activation of light sensitive drugs in a spatiotemporal manner.
So what’s the next step? The authors now hope to harness cellular energy to create the short input pulses of light needed to make fully biological microlasers. Trip the light fantastic, and enlighten yourself with this new study in Nature Photonics, July 2015.