Stanford scientists look deeper into the body with new fluorescent dye

Glowing dyes help scientists see inside the body and diagnose ailments, but they needed a certain type of molecule to improve the imaging depth. Researchers invented a long wavelength near-infrared fluorescent molecule, and it works.

Physicians and researchers have increasingly turned to glowing dyes to look beneath the skin. An eye doctor, for example, might inject a dye into a patient’s blood before shining a bright light in her eye. The dye causes the blood vessels to glow, providing a roadmap of the patient’s retina on a computer screen.

At Stanford and elsewhere, researchers have worked to create dyes that, when stimulated, emit light of long wavelengths close to infrared light. Such a light, which is not visible to the human eye, could then be viewed by a special camera and be projected to a monitor to produce deeper, sharper images from inside the body.

This fluorescent imaging can help to pinpoint tumor locations near the skin’s surface in a variety of cancers, such as head and neck, melanoma and breast cancer.

The NIR-II dye can resolve blood vessels in the forelimb as well as the brain with unprecedented clarity. The dye also allows clear resolution of tumors in the center of the mouse’s brain.

Nature Materials – A small-molecule dye for NIR-II imaging