Light delivered via an optical fiber is used in medicine for tasks such as examination of tissues and destruction of tumors. Many other applications are on the way, including drug release and activation, optogenetics, and new diagnostic modalities. Some of these may require a source of light to be available for long periods of time. A major challenge with using a traditional fiber to reach a target deep inside the body for extended time periods is that it’s usually made of brittle, non-biodegradable glass. It therefore has to be removed eventually without leaving any parts behind.
Now researchers at Pennsylvania State University have developed a completely biodegradable step-index optical fiber out of a citrate-based polymer. Step-index fibers feature a central channel through which light passes and an exterior coating that prevents light from escaping. It can be used to both deliver light and to look at objects at the distal end of the fiber.
Both the inner layer and the outside have precisely the same mechanical properties, which means that the total fiber can be bent and stretched without having the two layers separate from each other. Additionally, the layers biodegrade at a similar rate with each other, disappearing into the body and leaving it via normal and commonly used channels.
“We believe this new type of biodegradable, biocompatible and low-loss step-index optical fiber can facilitate organ-scale light delivery and collection,” Shan said. “And that it will become an enabling tool for diverse biomedical applications where light delivery, imaging or sensing are desired,” Dingying Shan, a Ph.D. student that worked on the research.
Study in journal Biomaterials: Flexible biodegradable citrate-based polymeric step-index optical fiber…
Via: Penn State…
