No no, no no no no, no no no no, no no there’s no limit!
Overcoming the diffraction limit — the fundamental maximum resolution of a lens and its ability to differentiate between two sources — has been a major barrier in optical microscopy and the ability to obtain high-resolution images in biophysical and biomedical research. For example, being able to clearly see and study living cells and organism such as bacteria, proteins and DNA. In order to circumvent this limit, researchers have developed “super-resolution microscopy”: the umbrella term for several techniques which go beyond the diffraction limit, most of them to the nanometre scale. Some examples include:
- STED: stimulated emission depletion fluorescence microscopy
- RESOLFT: reversible saturable optical fluorescence transitions
- PALM/STORM: photo-activated localization microscopy/stochastic optical reconstruction microscopy
- SSIM: saturated structured illumination microscopy
- CSREM: correlative super-resolution optical and electron microscopy
Progress in this field received the ultimate scientific recognition when Eric Betzig, Stefan Hell and William E Moerner were awarded the 2014 Nobel Prize for Chemistry for their work. Now, hot of the heels of that accolade, comes “The 2015 super-resolution microscopy roadmap” published in Journal of Physics D: Applied Physics (J. Phys. D: Appl. Phys. 48443001). Organised by researchers Professor Christian Eggeling (University of Oxford) and Dr Mark Bates (Max Planck Institute for Biophysical Chemistry), the article compromises fifteen two-page sections written by an expert, each describing a particular approach, or an aspect of an approach, to super-resolution microscopy. Professor Eggeling explained:
“Super-resolution optical microscopy has been one of the most momentous developments in life science over the last decade. Still, a lot of confusion exists on what the various super-resolution techniques can really accomplish in biological research and what the upcoming challenges are.”
The roadmap covers a wealth of topics associated with super-resolution microscopy, including the use of adaptive optics, optical calibration using DNA-based reference samples, and using fluorescent nanobodies as protein tags to name a few.
You can read the roadmap here and hear more from Professor Eggeling and Dr Bates on medicalphysicsweb: Beyond the diffraction limit: super-resolution microscopy.
This work is licensed under a Creative Commons Attribution 3.0 Unported License. Images: Stefan W Hell et al 2015 J. Phys. D: Appl. Phys. 48 443001
Categories: Journal of Physics D: Applied Physics