Semi-distributed fiber-optic interferometer as a simple and rapid sensor for detection of cancer biomarkers

In this work, we report the realization of a fiberoptic biosensor suitable for the detection of cancer biomarkers, and having a rapid and scalable fabrication method. The biosensor is based on a short span of a high-scattering fiber, cleaved on the fiber tip; the reflectivity present in the fiber due to Rayleigh scattering combines with the fiber tip to form a semi-distributed interferometer (SDI), having quasi-periodic spectrum with average sensitivity -259 dB/RIU (refractive index units). The sensor was then functionalized for the detection of Chemokine ligand 5 (CCL5) cancer biomarker over a wide range (10 fM – 10 nM), showing a log-quadratic response. The SDI sensor is a simple, real-time, and high-performance biosensor suitable for in-situ detection of biomarkers.