Biosensors & Bioelectronics

Development of Surface Plasmon Resonance (SPR) Based Immuno-Sensing System for Detection of Fungal Teliospores of Karnal Bunt (Tilletia indica), a Quarantined Disease of Wheat

Abstract

Sadhna Singh, Manoj Singh, Gohar Taj, Sanjay Gupta and Anil Kumar

This paper first time describes Surface Plasmon Resonance (SPR) based immuno-sensing system for detection of fungal teliospores of Karnal Bunt (KB) disease of wheat incited by Tilletia indica. The results of present study were compared with the results of lab scale ELISA developed earlier in our lab. The approach involves the use of a rabbit polyclonal (anti-teliospore) antibody and a SPR sensor for label-free detection of teliospores from the model organism Tilletia indica. When the interaction between binder (anti-teliospore antibody) and teliosporic antigen(s) as analyte occurs at the sensor surface, a sensorgram was obtained in real time by plotting the signal against time. Under optimised assay conditions as few as 5 teliospores were detected by ELISA which justifies the greater affinity of raised anti-teliospore antibodies for its antigen. The sensitivity of each immunosensor constructed with
the different amounts of antigen solution is determined by sensogram analysis showed detection sensitivity as low as 625 pg equivalent to 2.5 teliospores over the sensor surface by getting an angle of dip indicating greater affinity of raised anti-teliospore antibodies. Thus, SPR based affinity sensor showed higher sensitivity due to greater signal response. The results of cross reactivity studies using different related fungal spores/teliospores showed almost differential SPR response indicating cross reaction using immunosensing system. The cross-reactivity of anti-teliospore antibodies with related fungal spores/teliospores can be explained due to its polyclonal nature and also due to antigenic homology amongst pathogens used in present study.