In Living Color — Fluorescent proteins (FPs) have revolutionized optical microscopy by allowing studies of living cells and tissues. In the June 16 online issue of Nature Methods, Dr. Vladislav Verkhusha and research fellow Dr. Daria Shcherbakova describe four new near-infrared FPs they’ve developed that allow for multicolor imaging of tissues deep within humans and other mammals. Such FPs are ideal for in vivo imaging because wavelengths in the near-infrared portion of the electromagnetic spectrum (650 nm to 900 nm) pass right through hemoglobin, melanin and water. The scientists derived the new FPs from photoreceptors called phytochromes that bacteria use to detect light. To test the performance of the four new FPs, the researchers took mouse breast cancer cells that expressed each FP and injected those cells into the mammary glands of mice, where the cancer cells grew into tumors. The FPs proved to be highly sensitive probes, allowing the tumors to be detected at very early stages. The near-infrared FPs could open up new possibilities for simultaneously labeling two or more tissues and for tracking several cell populations in a living animal. Dr. Verkhusha is professor of anatomy and structural biology.
Posted on: Monday, June 17, 2013