Abstract

Novel Fiber Optic Biosensors for Attomolar Analyte Detection

Raghavendra Sai V V, Assistant Professor, IIT Madras

Several sensor technologies for attomolar analyte detection have been developed in recent past. However, it is important to note the increasing level of sophistication and complexity of these technologies as the detection limits are pushed towards a few tens or single molecules. Here, we report a plasmonic fiber optic biosensor technology capable of attomolar analyte detection with the help of (i) a relatively simpler instrumentation consisting of a highly sensitive U-bent fiber optic sensor probe coupled to (ii) a pair of LED and photodetector and (iii) gold nanoparticle labels. The results based on this technology show a detection capability of 0.15 zeptomol (or 6 aM or 150 molecules) of human IgG molecules as analytes. The initial results with the help of lock-in amplification based detection show an ability to further improve the detection limit of the sensor by an order. The overall cost of the system is less than INR 1 Lakh as of now. However, the integrated system should be less costlier and could potentially open-up scope for development of highly sensitive point-of-care clinical diagnostic devices.