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New light-sensitive polymer to control drug release from nanoparticles

One of the major challenges in using nanomedicine for drug delivery is how to get the nanoparticles carrying the therapeutic drug to release the drug when they arrive at the proper place. Thanks to Jessica Moore of the Center of Excellence in Nanomedicine, University of California, San Diego for sending news of a new polymer that degrades in response to near infrared light. Because near infrared light penetrates several inches through human tissue, it could be used to control the release of drugs from nanoparticles lodged in specific locations. From the American Chemical Society’s press release “New “smart” material could help tap medical potential of tissue-penetrating light“:

… Scientists are reporting development and successful initial testing of the first practical “smart” material that may supply the missing link in efforts to use in medicine a form of light that can penetrate four inches into the human body. …

Adah Almutairi and colleagues explain that near-infrared (NIR) light (which is just beyond what human can see) penetrates through the skin and almost four inches into the body, with great potential for diagnosing and treating diseases. Low-power NIR does not damage body tissues as it passes. Missing, however, are materials that respond effectively to low-power NIR. Plastics that disintegrate when hit with NIR, for instance, could be filled with anti-cancer medicine, injected into tumors, and release the medicine when hit with NIR. Current NIR-responsive smart materials require high-power NIR light, which could damage cells and tissues. That’s why Almutairi’s team began research on development of a new smart polymer that responds to low-power NIR light.

Hit with low-power NIR, their new material breaks apart into small pieces that seem to be nontoxic to surrounding tissue. …

The news section of the journal Science featured an article by Robert F. Service “Building a Breakable Capsule“:

Therapeutic drugs sometimes inflict more damage than they cure. One solution to this problem is to enclose the drugs inside a capsule, shielding them from the body—and the body from them—until they can be released at just the right spot. There are lots of ways to trigger this release, including changing temperature, acidity, and exposure to magnetic fields. But triggers can come with their own risks—burns, for example. Now, researchers in California have designed what could be the most benign trigger to date: shining near-infrared light (NIR) on the encapsulated drug. …

… Almutairi says she and her colleagues plan to test whether the compound is useful for slowly releasing therapeutic proteins into the eye to treat macular degeneration.

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