Fluorescent near-infrared waves pass readily through a mouse's tissues to reveal its brightly glowing liver, thanks to the use of iRFP protein (Image: Albert Einstein College of Medicine)
There are several techniques used by researchers and physicians to image the internal organs of people and animals, but each of these techniques have their shortcomings. X-rays and computed tomography (CT) scanning, for instance, involve exposing the subject to radiation. Magnetic resonance imaging (MRI) is safer, although subjects must sometimes ingest a contrasting agent in order to obtain more distinct images. The use of injected colored fluorescent proteins is another approach, but has been limited by the fact that hemoglobin in the subject’s blood absorbs much of the wavelength of the light used for imaging. Now, however, scientists from New York’s Albert Einstein College of Medicine of Yeshiva University have engineered a new fluorescent protein that sidesteps this limitation.