Bioresorbable fibers for time-domain diffuse optical measurements: a step toward next generation optical implantable devices

摘要

The use of bioresorbable fibers represents an innovative way to build optical implantable devices and to look inside thebody. Recently, a new kind of bioresorbable fibers, based on calcium-phosphate glasses, has been introduced by some ofus. They show a good biocompatibility and improved attenuation loss coefficient with respect to other bioresorbablefibers. In this work, we used those fibers to explore their suitability in diffuse optics. Indeed, the time-domain techniqueis a non-invasive methodology which allows to have an absolute estimate of the absorption and reduced scatteringspectra of the diffusive medium. It allows to bring information about concentration of chemical components (water, oxyanddeoxy-hemoglobin), thus conveying information about the functional status and/or the scattering properties (changesin tissue microstructure, edema). Such information can then be related to the tissue regeneration, healing process, or to aharmful evolution. This makes the time domain optical spectroscopy coupled to bioresorbable fibers a good candidate forfuture medical devices. Here we demonstrate the suitability of these fibers for diffuse optics by means of standardizedtests and then we use them for a proof-of-principle measurement on ex-vivo chicken breast, obtaining results comparablewith standard fibers. Thanks to the encouraging results, we are working on a system based on a single fiber (serving asboth injection and collection fiber) to go closer to a single interstitial fiber which can lessen the effect of the implant.