Waterborne diseases constitute 80% of world diseases as per WHO. The pathogens can either grow or can persist in water. WHO recommends continuous monitoring of indicator pathogens such as E. coli or thermotolerant coliforms, Clostridium perfringens, coliphages, etc. and suggests their prevalence less than 1 colony forming unit in 100 mL. Given the wide spectrum of these pathogens, simultaneous detection of a set of pathogens prevalent in a region of interest is necessary. The conventional techniques for pathogen detection including culturing and microscopic examination are time consuming and laborious. The spectroscopic techniques lack sensitivity. On the other hand, the advanced molecular (nucleic acid based) techniques for single and multiple pathogen detection require sophisticated instruments and/or skilled personnel. To overcome these limitations, several biosensor array systems have been developed, considering the need for multiplexed real-time pathogen detection. These biosensor arrays mainly rely on optical, electrochemical or mass-sensitive transducers. A variety of optical transducers have been reported based on microfabricated waveguide or optical fibers with/without grating structures as well as surface plasmon resonance to enhance their sensitivity. Some of the commercially available devices include EWA based optical fiber devices (e.g. RAPTOR, Analyte 4000/ 2000 and Octet), SPR based devices (e.g. ProteOn XPR36) etc. These systems are robust and sensitive but limited mainly to research applications.

A novel array Fiber optic Absorbance Biosensor (ArFAB) for multiplexed pathogen detection is proposed that works with the principle of fiber optic evanescent wave absorbance of protein molecules at 280 nm. The in-house developed device consisting of 8 sensor channels, accommodate U-bent fiber optic sensor probes, incorporated with a UV-LED and CMOS line detector for continuous monitoring of pathogens in water. The design, architecture and preliminary results from the ArFAB will be discussed in this seminar followed by the future work plan on development of plasmonic probes for ArFAB.