New 'smart' material could help tap medical potential of tissue-penetrating light

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 researchers envision, for instance, putting the polymer in an implantable "hydrogel," which is a water-containing flexible material used for tissue engineering and drug delivery. A hydrogel with the new polymer could release medications or imaging agents when hit with NIR. "To the best of our knowledge, this is the first example of a polymeric material capable of disassembly into small molecules in response to harmless levels of irradiation," say the researchers.

The authors acknowledge funding from the NIH Director's New Innovator Award and King Abdul Aziz City of Science and Technology.