Super-resolution microscopy ditches fluorescent tags for gentler imaging of live cells

A new super-resolution microscopy technique has allowed researchers to see features in materials and living organisms at resolutions far finer than the diffraction limit without the need for fluorescent labels. This makes it easier and less disruptive than previous techniques, and could have broad applications, especially in biochemistry.

The wave nature of light limits the resolution achievable with simple microscopes. Light radiated by two point sources in the focal plane produces an interference pattern at the detector. If two point sources are less than half the wavelength of the light apart, interference fringes merge, making the objects indistinguishable. Typically, this means that light microscopes cannot resolve detail smaller than about 200nm. Advanced techniques use various imaginative tricks to overcome the diffraction limit, but all have their drawbacks, such as requiring large amounts of light that can damage living samples.