Microscopy Technique Breaks Through Color Barrier Of Optical Imaging

Recently, researchers at Columbia University enabled the breaking of "color barrier" of light microscopy for biological systems. They allowed for more comprehensive, system-wide labeling as well as imaging of a large number of biomolecules in living cells and tissues.

It was a development that promised a lot for future applications, apart from enabling therapies that can treat diseases, according to Phys.org. The study was published online April 19 in Nature. The team of scientists was led by Associate Professor of Chemistry Wei Min. The study talked about a novel optical microscopy platform that showed enhanced detection sensitivity. Moreover, the scientists also showed details of new molecules. When paired with the novel instrumentation, it allowed for parallel labeling and imaging of almost 24 specific biomolecules. This was almost five times the number of biomolecules that can be imaged simultaneously with available technologies.

"What makes our work new and unique is that there are two synergistic pieces - instrumentation and molecules - working together to combat this long-standing obstacle," Min said. Observing structures in living cells and tissues with some fundamental limitations includes a "color barrier." Fluorescence microscopy, for example, is extremely sensitive and, also currently used in biology labs. However, it is limited by the "color barrier," as researchers can see only five structures at a time due to the fluorescent proteins that are used to release a number of shades that are slotted into five broad color categories, according to Azootopics.

In addition to fluorescence microscopy, there are currently a variety of Raman microscopy techniques in use for observing living cell and tissue structures that work by making visible the vibrations stemming from characteristic chemical bonds in structures. Such conventional Raman microscopy creates highly-defined colors. But they do miss the sensitivity. It calls for a strong and concentrated vibrational signal. That that can be made possible only if there are millions of structures within the same chemical bond. If the signal from the chemical bonds is weak, it is also not possible to visualize the associated structure.

Min and his team, including Profs. Virginia Cornish (chemistry) and Rafael Yuste (neuroscience) combined the existing microscopy techniques to develop a novel platform called electronic pre-resonance stimulated Raman scattering (epr-SRS) microscopy combining the best of both worlds. They brought together high levels of sensitivity and selectivity. They used an innovative technique that identified specific structures with low concentration. They did not use millions of the same structure to locate the structure in conventional Raman microscopy. This novel instrument calls for just 30 for identification.

It is a method that also uses new sets of tagging molecules that have been designed by the team to work with the ultramodern technology. It is a "color palette" of molecules that expands tagging capabilities and permitted the imaging of almost 24 structures at a time instead of facing the limits of just five fluorescent colors. There is more promise for expansion in the future, believe the researchers.