Light microscope peers into cells

Scientists have developed a light microscope so powerful that it allows users to see inside cells and discern the precise location of nearly each individual protein they are studying.

The instrument was developed by the Howard Hughes Medical Institute’s Janelia Farm Research Campus in collaboration with researchers at the National Institutes of Health and Florida State University.

Conventional optical microscopes are inherently limited by the wavelength of light, meaning. Objects separated by less than 200 nanometres cannot be distinguished from one another. The new approach, called photoactivated localisation microscopy (PALM), can discriminate molecules that are only two to 25 nanometres apart.

The researchers employed spectroscopic near-field microscopy, where a spectrum of light is spread out across wavelengths. This was used alongside molecular biology techniques that allow scientists to attach a new type of fluorescent label to each copy of a protein they wish to study.