SRS microscopy helps track molecules and drugs in live cells
Armed with research concluding that psoriasis is associated with an increased risk of heart attacks and other cardiovascular conditions, Joel M. Gelfand, MD, MSCE, Assistant Professor of Dermatology at the University of Pennsylvania School of Medicine and colleagues released an editorial consensus in the American Journal of Cardiology today, calling for psoriasis patients to be
Full Post: 3.6 million Americans living with active, undiagnosed psoriasis, unaware of associated risks
A new type of highly sensitive microscopy developed by researchers at Harvard University could greatly expand the limits of modern biomedical imaging, allowing scientists to track the location of minuscule metabolites and drugs in living cells and tissues without the use of any kind of fluorescent labeling.
The technique, based on stimulated Raman scattering (SRS), works by detecting the vibrations in chemical bonds between atoms. SRS microscopy could provide scientists with a potent new form of real-time, three-dimensional bioimaging free of fluorescent labels that can hinder many biological processes.
The work is described this week in the journal Science by a team led by Harvard’s X. Sunney Xie, Christian W. Freudiger, and Wei Min.
“SRS microscopy is a big leap forward in biomedical imaging, opening up real-time study of metabolism in living cells,” says Xie, professor of chemistry and chemical biology in Harvard’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, Freudinger, and 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 says. “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.”
SRS microscopy could also prove useful in neuroimaging, since neurons are coated with fatty myelin sheaths.
The researchers’ use of SRS microscopy to analyze skin tissue could also open new frontiers in drug development. Xie and colleagues used SRS microscopy to view how well retinoic acid, a topical acne medication, is absorbed into skin cells. They also used the technique to capture deep-skin penetration by dimethyl sulfoxide (DMSO), a compound added to many topical medications and ointments to enhance absorption.
Scientists currently use a variety of techniques to visualize biomolecules, but most have significant limitations that are sidestepped by SRS microscopy. A jellyfish protein first discovered in 1962, green fluorescent protein (GFP), is now used extensively as a label for observing the activity of biomolecules. GFP labeling provides sharp images, but the bulky protein can perturb delicate biological pathways, especially in cases where its heft overwhelms smaller biomolecules. Also, GFP’s characteristic glow subsides with time, making it infeasible for long-term tracking.
Much like SRS microscopy, conventional infrared (IR) and Raman microscopies measure the vibrations of chemical bonds between atoms. But they are low-sensitivity imaging techniques, and require either desiccated samples or high laser power, which limits use in imaging live specimens. Coherent anti-Stokes Raman scattering (CARS) microscopy, a field pioneered by Xie’s own group, cannot provide clear enough contrast for most molecules.
A study published in the scientific journal PLoS ONE highlights how the exploration of the ocean depths can benefit humankind. This is the story of a voyage of discovery, starting with marine animals that glow, the identification of the molecules responsible and their application as marker in living cells. Many marine organisms such as sea
Full Post: Biomedical research could benefit from deep sea
In human relationships, a certain “spark” often governs whether we prefer one person to another, and critical first impressions can occur within seconds. A team lead by Johns Hopkins researchers has found that cell-to-cell “friendships” operate in much the same way and that dysfunctional bonding is linked to the spread of cancer. The research was
Full Post: Tiny protein provokes healthy bonding between cells
A leading international scientist will reveal how the latest techniques in microscopy - including time-lapse imaging of living cells - are leading to breakthroughs in understanding genetic and acquired diseases. In a public lecture next Tuesday to launch the Electron Microscope Unit’s Golden Jubilee Symposium, Professor Hans Tanke, the Head of the Department of Molecular
Full Post: How microscopy can unlock the key to disease
The report, entitled Cytosolic Phospholipase A2-: A Potential Therapeutic Target for Prostate Cancer, describes the possible role of an enzyme called cPLA2- in prostate cancer and its potential to be a treatment target for prostate cancers that no longer respond to hormone-related therapy. Hormone-related therapy is the first line of treatment for more advanced prostate
Full Post: Theraputic target for prostate cancer
Scientists have always wanted to take a closer look at biological systems and materials. From the magnifying glass to the electron microscope, they have developed ever-increasingly sophisticated imaging devices. Now, Niels de Jonge, Ph.D., and colleagues at Vanderbilt University and Oak Ridge National Laboratory (ORNL), add a new tool to the biology-watcher’s box. In the
Full Post: New technique images whole cells in liquid with a scanning transmission electron microscope