Thin-film-based optical fiber interferometric sensor on the fiber tip for endovascular surgical procedures.

Objective: Endovascular surgery requires accurate measurement of parameters such as pressure, temperature, and biomarkers within vessels for real-time tissue response monitoring and ensuring targeted therapeutic interventions. However, the availability of small tip-based sensors capable of precise application, for example, navigating an aneurysm's lumen, is limited. With their capabilities for real-time analysis, flexibility, and biocompatibility, optical fiber sensors (OFS) hold promise in addressing this need. This proof-of-concept study investigates the feasibility of OFS in endovascular surgery scenarios.

Methods: The sensor is based on a single-mode silica fiber with an interferometric forward-facing thin-film tip. The thin-film materials may be tailored for detecting various physical parameters and, when functionalized, also specific analytes. Materials applied in this sensor are thin metal oxides deposited using magnetron sputtering. A full-scale 3D-printed vascular model was employed to simulate endovascular setup.

Results: The experiments showed the high mechanical robustness of the approach, i.e., the sensor maintained functionality while being maneuvered through the endovascular model. The forward-facing tip remained intact and worked adequately, ensuring consistent and stable readouts. Moreover, the fiber showed sufficient flexibility, with no significant bending loss observed during simulations. Finally, the performance of the OFS in bovine serum samples was assessed. The sensor performed well in serum, and the results suggest that low-concentration serum may be used to reduce nonspecific surface interactions.

Conclusion: Overall, this OFS system offers a promising solution for endovascular surgery and other biomedical applications, allowing for precise and on-the-spot analysis.

Significance: Our study pioneers the feasibility of thin-film interferometric label-free OFS with a forward-facing sensitive area for sensing during endovascular procedures.