Rapid sensing of Tilletia indica – Teliospore in wheat extract by a piezoelectric label free immunosensor

Abstract

‘Tilletia indica’, a fungal pathogen causes Karnal bunt disease in wheat. It has been renowned as a quarantine pest in more than 50 countries, therefore, urged a threat to wheat in the international market. To date, conventional methods employed to detect the disease involve the tentative identification of spores (teliospores) based on morphology. For effective and specific disease control, it is essential to get the specific protein of the analyte (teliospore) to target. In present study, a label-free immunosensor has been developed to detect Karnal bunt disease. A specifically synthesized anti-teliosporic monoclonal antibody (mAb) was immobilized on a self-assembled monolayer of 11-mercaptoundecanoic acid (11-MUA) to detect teliospore. All modified electrodes were morphologically characterized by scanning electron microscopy (SEM), atomic force microscopy(AFM), Fourier transform infra-red spectroscopy (FT-IR) techniques and analytically characterized by quartz crystal microbalance (QCM) and cyclic voltammetry (CV). The linearity range was 19 pg mL−1–10 ng mL−1, while the detection limit (LOD) was 4.4 pg mL−1 and 12.5 pg mL−1, respectively. The stability, reproducibility, and repeatability of the immunoelectrode was examined by CV, and found stable upto 18 days with negligible variation. The binding affinity (association constant (Ka)) of the developed immunoelectrode was 1.9 × 10−2 ng mL−1. The real sample has been tested in spiked wheat samples and found about 95–103 % recovery with 2.8–4.4 % relative error.