Blood becomes a laser emitter for drug testing, cancer treatment

Researchers at the University of Michigan (Ann Arbor, MI) have developed a new technique that combines laser light with an FDA-approved green fluorescent dye to monitor cell structure and activity at the molecular level. The work could someday improve clinical imaging and better monitor tumors and other cell structures, as well as be used during drug testing to monitor the changes that cells undergo when exposed to prospective new drugs.

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The team—led by Xudong (Sherman) Fan, associate professor in Biomedical Engineering at the University of Michigan—shined laser light into a small laser cavity containing whole human blood infused with indocyanine green fluorescent dye. By analyzing the light that was reflected, the researchers could observe cell structures and changes within the blood on the molecular level.

Because the technique has the ability to process laser light, it can be amplified to make small changes easier to see or filtered to remove unwanted background noise. Current methods use similar dyes with infrared or visible light, relying on visible fluorescence to observe cell activity and making small changes can be difficult to see.

Currently, the researchers have only demonstrated the technique on whole blood outside the body. But they predict that in the future, they may be able to use it on tissue inside the body. This could enable better monitoring of cell activity and tissue properties inside the body, or enable a surgeon to precisely identify the edge of a tumor during guided surgery.

Full details of the work appear in the journal Optica; for more information, please visit http://dx.doi.org/10.1364/optica.3.000809.