Sensitive and highly specific DNA-based impedimetric detection of Ralstonia solanacearum in infected potato tubers without PCR amplification*

An efficient, fast, and label-free method for detecting DNA hybridization directly on the biofunctionalized electrode as a signature for real-time pathogen detection is non-faradaic electrochemical impedance spectroscopy (nf-EIS). In this article, we describe the identification of diseased potato tubers using an impedimetric biosensor that is more sensitive than conventional methods. From several parts of Goa, India, diseased potato tubers are collected and evaluated using nf-EIS measurements. A specific DNA probe for R. solanacearum, lpxC4, is immobilized on micro fabricated gold interdigitated electrodes (IDE) to act as a sensing platform using a standardized two-step assembly procedure. The developed sensor is essentially free of prior target labeling and polymerase chain reaction (PCR) amplification and is very reproducible. This study should be a valuable resource for the development of extremely accurate and sensitive biosensors for the detection of agricultural pathogens.