Heart-shaped nano beads
The image below shows how a cluster of beads, each 170 nanometres in size, looks under a standard diffraction-limited optical microscope. The image on the right demonstrates the capability of the National Physical Laboratory's super-resolution microscope that uses structured illumination to bypass the diffraction limit and visualise the individual beads.
Biotechnologists at the National Physical Laboratory (NPL) specialise in the measurement of biomolecules in solution, at interfaces and in cells and tissues. They examine the benefits and limitations of different measurement techniques and improve them so that measurements are more robust, comparable, sensitive and accurate.
The best achievable resolution of an optical imaging system due to diffraction is around 250 nanometres, which is too great to directly examine the behaviour of molecules and structures within cells.
Super-resolution imaging methods such as the Structured Illumination Microscopy (SIM) demonstrated above and direct Stochastic Optical Reconstruction Microscopy (dSTORM) can distinguish between fluorescently-labelled molecules and structures located less than 120 nanometres or 40 nanometres apart, respectively.
These techniques bridge a gap between the confocal and electron microscopes typically used by cell biologists, and their adoption will greatly aid understanding of important molecular processes underlying cell behaviour, for example secretion and endocytosis.
More on NPL's work in Biotechnology
Find out more about Super Resolution imaging
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