Recent Advances in Optical Biosensors for Sensing Applications: a Review

Merging engineering with medical science and adopting artificial intelligence to get further exact results specifically for preventive health care has made it challenging to detect the concentration or presence of biological analytes. The basic building blocks of such a system require recognition of an analyte, producing a signal that must be passed through a signal conditioning unit, and, finally, a detector that recognizes the specific analyte. The detection extends to the sensing of bacteria, tumor cells, tumor biomarkers, toxins, drugs, and other biomarkers with admirable accuracy with sensitivity. In optical biosensors, most commonly, it is the fluorescence technique. It measures the intensity, decay time, quenching efficiency, anisotropy, and quenching. Use plain sensor stripes, optical waveguide systems, arrays, and capillary-based technical sensors. This paper deals with the study of available optical biosensors, mentioning their working principle, merits, demerits, and application. The prime focus of this current study is the most widely used surface plasmon resonance (SPR) relied optical biosensors, including SPR imaging, and magneto-optical surface plasmon resonance. With this, some other optical biosensors are discussed, like evanescent wave fiber optic biosensor, evanescent wave fluorescence, and colorimetric polymerase chain reaction–based biosensor, as well as interferometric, ellipsometric, surface-enhanced Raman scattering biosensors, and Photonic crystal fiber sensor.