Fiber grating sensors and their recent applications in biomedical domain

Sensors play an important role in measuring various physio-chemical and biological parameters. Biomedical applications of sensors include early level diagnosis of diseases, treatment technique enhancement and also monitoring the effect of medical techniques using suitable biomedical devices. The sensors which are deemed suitable for biomedical applications need to be fast, accurate, flexible, small, and most importantly, biocompatible. The inherent advantages of fibre optic sensors, such as small foot print, electrical passiveness, multiplexing capability and fast response make them the most preferred for biomedical sensing applications. Fibre optics sensors are generally used in the measurement of parameters such as temperature, strain, pressure, displacement, angle, and force. And find applications in diverse regimes like structural health monitoring, shape sensing, seismic sensing; in the bio medical domain, they have been deployed in gait analysis, pulse rate monitoring, body joint angle measurements, acquisition of respiratory parameters, cardiovascular parameters and many more. Despite being a topic of significant interest in biomedical applications, the adoptablility of optical sensors in clinical practice is not very encouraging. Hence, there is a need to address the reasons for the same, and the present review aims to highlight some critical areas. The present review paper primarily discusses the optical fibre grating techniques: their fabrication methods, the applications of these sensors in biophysical and biomechanical measurements, bio proteins and biomarker detection in body fluids. The review also discusses the bottlenecks in the clinical application of these sensors. The comparison of the performance of the optical fibre sensors with other sensing techniques is also discussed in this review paper.