Researchers have developed a method that combines a deuterium (D2O) tracer and Raman scattering (SRS) to give a close-up view of changes occurring in individual live cells, according to a study published today in Nature Communications. The new technique has potential applications in helping surgeons precisely remove tumors, or in detecting head injuries and developmental and metabolic disorders.
The technique was developed by researchers at Columbia University and takes advantage of the fact that deuterium is safe for human consumption in small doses (no more than five tablespoons for humans). Once ingested, D2O is incorporated into newly made macromolecules, where it forms chemical bonds with carbon.
When these newly formed carbon-deuterium bonds are hit with light, they vibrate at varying frequencies, allowing them to be identified as either a protein, lipid, or DNA in an animal’s brain, skin, gut, and other organs. Unlike other techniques, such as the combination of mass spectrometry and D2O to track proteins and lipids in extracted cells, this method allows real-time tracking in living subjects.
To test the method, researchers diluted water with D2O and gave it to roundworms, mice and zebrafish embryos to drink, then watched the proteins, lipids and DNA form. In one such experiment, they watched a bright line emerge around fast-growing brain and colon tumors in mice. "This method creates a sharp line between healthy and cancerous tissue, making it much easier to remove the tumor," said the study's co-lead author, Lingyan Shi, a postdoctoral researcher at Columbia.
In other such observations, the researchers watched fat production rise and fall in an aging worm’s reproductive system, the formation of the myelin sheath in developing mice, and the formation of lipids around the sweat glands of mice. These experiments demonstrated the applications for this technique in better understanding cell development and aging.
Image: As living cells absorb heavy water, deuterium is incorporated into newly made proteins, lipids and DNA. When the researchers aimed the light of a stimulated Raman scattering (SRS) microscope at a single cell, each of the macromolecules above could be identified within. Image courtesy of Wei Min lab/Columbia University.