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2016-01-05 17:19:52, Hit : 1,248, Rec. : 483 |
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Stanford Univ. scientists developed new molecular fluorescent dyes capable of being injected into the patient that both improve imaging depth and safety compared to previous dyes.
¡°Fluorescent imaging of biological systems in the second near-infrared window (NIR-II) can probe tissues at centimeter depths and achieve micrometer-scale resolution at depths of millimeters,¡± the researchers wrote in their paper appearing in Nature Materials. ¡°Unfortunately, all current NIR-II fluorophores are excreted slowly and are largely retained within the reticuloendothelial system, making clinical translation nearly impossible.¡±
The technology has potential use as a diagnostic tool.
Already, dyes are used in the medical field. Doctors inject a dye into patient's bloodstream in an eye test known as fluorescein angiography. The dye travels from the arm to the blood vessels in the eyes in a matter of seconds, giving doctors a view into the blood vessels¡¯ configuration.
For a while, researchers have worked at creating dyes that emit long wavelengths near infrared light. Such a dye would be capable of being viewed via a special camera and projected on a monitor. The long wavelengths ensure the light escapes from the skin with negligible scattering, allowing for better images.
However, there are safety concerns. According to Stanford Univ., ¡°Some (dyes) made from carbon nanotubes or quantum dots can linger in the body for days and months, caught in the liver and spleen, before being excreted slowly.¡± This has prevented the technologies implementation in humans.
The new dye, according to the researchers, is 90% excreted through the kidneys within 24 hours. ¡°The fluorophore outperformed indocyanine green (ICG)—a clinically approved NIR-I dye—in resolving mouse lymphatic vasculature and sentinel lymphatic mapping near a tumor,¡± the researchers wrote.
¡°The difficulty is how to make a dye that is both fluorescent in the infrared and water soluble,¡± said Alex Antaris, the first author of the paper. ¡°A lot of dyes can glow but are not dissolvable in water, so we can¡¯t have them flowing in human blood. Making a dye that is both is really the difficulty. We struggled for about three years or so and finally we succeeded.¡±
The researchers believe the dye has applications as a surgical guide, as it can be captured in video in real-time.
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