Orchid Virus Detection from Orchid Leaves Using Micro/Nano Hybrid-Structured Immuno-Electrochemical Biosensor

Abstract

In this study, a label-free detection approach for effective detection of Odontoglossum ringspot virus (ORSV) in orchids was developed. We used a semiconductor fabrication process to fabricate 1,810 micro/nano hybrid-structured sensing electrodes on an 8-inch reclaimed silicon wafer. The commonly used self-assembled monolayer (SAM) process was then employed to sequentially modify the electrode surface with 11-mercaptoundecanoic acid (11-MUA), 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide (EDC)/N-hydroxysuccinimide (NHS), and anti-ORSV. Electrochemical impedance spectroscopy (EIS) was utilized for ORSV concentration detection. The experimental results demonstrated that the ORSV concentration in the virus-infected orchid leaves could be effectively detected. Compared with the commercial enzyme-linked immunosorbent assay (ELISA) kit, our device possesses a wider linear detection range (0.5–50,000 ng ml−1), higher sensitivity (218.07 kΩ/ng/ml). A lower limit of detection (0.238 ng ml−1) was calculated using the 3σ formula. The specificity of our device on ORSV detection was also confirmed. Our sensing device features advantages such as label-free detection, the use of lower amounts of antibody and few sample tissues, short detection time, and a wider linear detection range. These results indicate the feasibility of our sensing device in field applications.