Microscopy has made huge leaps in recent years. With “nanoscopy”, a set of super resolution microscopy techniques, scientists can take their research to the next level.
Among the bio-imaging techniques that exist today, optical microscopy is ideal for studying live cells.
Although optical microscopy is an essential tool for biologists, it does have a set of limitations.
In addition to its ability to visualize only a few individual cells, this optical imaging technique has a very limited spatial resolution that prevents biologists from seeing deep inside the structure of an object.
For this resolution barrier, we have light diffraction to blame, something scientists have been aware of for a long time.
Abbe’s Diffraction Limit
Depending on the wavelength of the light used, microscopes can be sharp only up to a certain limit.
There is a certain point beyond which microscope lenses, regardless of their quality, can’t reveal the finer structural details of a specimen.
Despite the considerable advances in the design of lenses and dramatic improvement in image resolution, microscopes still suffer from the same diffraction barrier.
The reason behind this resolution limit has been known since the 19th century.
Thanks to the work of German physicist Ernst Abbe it’s been established that light diffraction intrinsically hampers the spatial resolution of any optical imaging instrument.
Microscopes, telescopes, and optical tools, in general, can’t discern objects smaller than half the wavelength of visible light, or 0.2 micrometers.
Set by physical rules, Abbe’s diffraction limit is a serious impediment to biological investigation.
Nanoscopy: Super Resolution Microscopy That Bypasses the Diffraction Limit
In recent years, many new imaging techniques that can sidestep the light diffraction barrier have emerged.
In 2014, The Royal Swedish Academy of Sciences awarded the Nobel Prize in Chemistry to Eric Betzig, Stefan W. Hell, and William E. Moerner.
The trio of scientists earned this distinction due to their ability to develop optical fluorescence methods that aided in circumventing the Abbe limit.
Thanks to the work of Betzig, Hell, and Moerner, nansocopes emerged as a new breed of microscope that don’t stop at the 0.2 micrometers limit.
Nanoscopes and Temporal Resolution
In a recent development, scientists at EPFL in Switzerland have announced another breakthrough that takes microscopy to new territory.
Refered to by its developers as a “4D microscope”, PRISM is a super-resolution microscope capable of both spatial and temporal imaging.
PRISM has the capabilities of both phase imaging (high temporal resolution) and fluorescence microscopy (high spatial resolution).
“We offer PRISM as a new microscopy tool and anticipate that it will be rapidly used in the life science community to expand the scope for 3D high-speed imaging for biological investigations,” said sTheo Lasser, leader of the study. “We hope that it will become a regular workhorse for neuroscience and biology.”
In the microscopic world, a second is a very long time. Biological processes happen on very short timescales well under a full second. Due to this, microscopes need to have, besides spatial resolution, temporal resolution.
Until now, super resolution microscopy came only with spatial resolution and no high time resolution.
This new development will give scientists a more informative platform to study the microscopic world in far more detail.
EPFL’s PRISM will be a powerful tool in the arsenal of biologists and neuroscientists. This new super resolution microscopy technique will enable researchers to investigate ever-changing and fast biological dynamics and chemical reactions on an unprecedented scale.