Futuristic microscopy to track molecules, drugs in live cells


Washington : A highly sensitive microscopy could greatly expand limits of biomedical imaging, allowing scientists to track minuscule metabolites and drugs in living cells and tissues.

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The technique, based on stimulated Raman scattering (SRS), works by detecting the vibrations in chemical bonds between atoms.

It could provide scientists with a potent new form of real-time, 3-D bio-imaging free of fluorescent labels that can hinder many biological processes.

“SRS microscopy is a big leap forward in biomedical imaging, opening up real-time study of metabolism in living cells,” said Sunney Xie, professor of chemistry and chemical biology in Harvard University’s faculty of arts and sciences.

“We’ve already used the technology to map lipids in a live cell, and to measure diffusion of medications in living tissue. These are just two early examples of how SRS microscopy may impact cell biology and medicine.”

Xie, his associates Christian W. Freudiger and Wei Min’s mapping of saturated and unsaturated fats in live cells offers exciting new opportunities for metabolic studies of omega-3 fatty acids, required but not produced by the human body.

Despite a growing body of evidence suggesting that omega-3 fatty acids provide many health benefits such as dampening inflammation, lowering blood triglyceride levels, and killing cancer cells, almost nothing is known about how fats like omega-3 are actually processed by our bodies.

“Our diets have changed greatly in recent decades,” Xie said. “As a unique technology capable of observing fat distribution in live cells — and of differentiating between types of fat, SRS microscopy could prove useful in helping understand and treat the growing imbalance of saturated and unsaturated fats in our diets.”

Scientists currently use a variety of techniques to visualise biomolecules, but most have significant limitations that are sidestepped by SRS microscopy, said a Harvard release.

A jellyfish protein first discovered in 1962, green fluorescent protein (GFP), is now used extensively as a label for observing the activity of biomolecules.

SRS microscopy does not require GFP labelling. It provides sharp images, but the bulky protein can perturb delicate biological pathways, especially in cases where its heft overwhelms smaller biomolecules.

The work is described this week in Science.