Water excited by infrared light melts nanoparticles to release drugs

Water heated by an infrared light allows for the release of a contained drug.--Courtesy of UCSD

Many drug delivery systems incorporate complex compounds designed to deliver precise doses to a desired target. Researchers at the University of California, San Diego, though, have developed a platform that uses as its main delivery function a substance familiar to us all: water.

The nano engineers published a study in the journal ACS Nano describing a system that uses near-infrared light from a laser to heat water inside nanoparticles that also contain drugs. The water heats to an extent that it melts the polymer nanoparticle shell, releasing the drug at a targeted position. Because of the simplicity of the process, it can be done repetitively, which allows for precise control over the dose, according to a report from the university.

What sets this method apart from other infrared releases is that water does not require as high-powered a laser as other "designer" polymers, and the overall result could potentially be less intrusive in the body of a patient. The wavelength of the infrared light needed to excite water molecules is less difficult to achieve than with other materials.

"A key advantage of this mechanism is that it should be compatible with almost any polymer, even those that are commercially available," co-lead author Mathieu Viger said in a statement. "We've observed trapping of water within particles composed of all the biodegradable polymers we've so far tested."

The method, funded by a National Institutes of Health New Innovator Award and an NIH grant, could also be used in other light-activated materials, the UCSD team says, including sunscreens and pesticides, in the future.

- here's the UCSD report

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