New Light-Sensitive Polymer For Use In Non-Invasive Surgical Procedures Developed

in technology, medicine

Scientists at the University of California, San Diego have developed what they believe to be the first polymeric material that is sensitive to biologically benign levels of near infrared (NRI) irradiation, enabling the material to disassemble in a highly controlled fashion.

The study represents a significant milestone in the area of light-sensitive material for non-invasive medical and biological applications. 

The research, supported by the prestigious NIH Director's New Innovator Award, is published online this week in the journal Macromolecules.

The design relies on the photolysis of the multiple pendant 4-bromo7-hydroxycoumarin protecting groups to trigger a cascade of cyclization and rearrangement reactions leading to the degradation of the polymer backbone.

photolysis of polymer by infrared
 The near infrared irradiation triggers a cascade of reactions leading to the degradation of the polymer backbone.
Image provided to ScienceDebate.com by UCSD
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“To the best of our knowledge, this is the only polymeric material specifically designed to break down in to small fragments in response to very low levels of NIR irradiation,” said Adah Almutairi, PhD, assistant professor at the UCSD Skaggs School of Pharmacy and Pharmaceutical Sciences and director of the Laboratory of Bioresponsive Materials at UC San Diego. “The material was also shown to be well-tolerated in cells before and after irradiation.  We think there is great potential for use in human patients, allowing previously inaccessible targets sites to be reached for both treatment and diagnosis.”

 Adah  Almutairi    

The properties of so-called “smart” polymeric materials – either synthetic or natural – respond readily to small changes in their environment.  They are, therefore, the focus of widespread research to develop tools for such uses as tissue engineering, implants, wound-healing, drug delivery and biosensors.

NIR light can penetrate up to 10 cm into tissue with less damage, absorption and scattering than visible light, and can be remotely applied with high spatial and temporal precision. According to the authors, "despite its potential for various medical and biological applications, there is a dearth of biomaterials that are responsive at this wavelength region.
 
Most other light-degradable materials that have been developed to date can be difficult to clear from the body, and only a handful of organic materials respond to high-power NIR light.  Until now, none were able to respond to low-level, thus safer, NIR light – which causes less photodamage to tissue and cells.

The UC San Diego researchers stated that further studies are warranted to improve the sensitivity of these smart polymeric materials to NIR, and they are currently pursuing several synthetic and engineering strategies to improve design of such biomaterials.

Source Article: Low Power, Biologically Benign NIR Light Triggers Polymer Disassembly. Nadezda Fomina, Cathryn L. McFearin, Marleen Sermsakdi, José M. Morachis, and Adah Almutairi. Macromolecules. Publication Date (Web): September 30, 2011. DOI: 10.1021/ma201850q.

Additional Source: University of California, San Diego 
 

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