Signal enhancing gold nanorods (GNR) and antibody modified electrochemical nanosensor for ultrasensitive detection of Japanese Encephalitis Virus (JEV) secretory Non-Structural 1 (NS1) biomarker

Abstract

Japanese Encephalitis Virus (JEV), a zoonotic infectious disease is a major concern in East-Asian and Western Pacific regions with no available therapy or fool-proof vaccines. Hence it is imperative to develop diagnostic assays for rapid mass screening for JEV biomarkers in human as well as pigs for better management of this recurring epidemic and guided therapy of infected patients. In this research work, we have exploited the advantages of gold nanorods (GNR) as signal enhancers which include ease of bioconjugation, on fabricated electrodes coupled with Non-Structural 1 (NS1) antibodies (Ab) of Japanese Encephalitis Virus (JEV) for ultrasensitive detection of JEV NS1 protein, which is found secreted in the circulatory system of infected individuals. Each fabrication, and conjugation step was thoroughly characterised and the electrode was optimised for various testing parameters. JEV NS1 antigen (Ag) recognition using the optimised electrode was carried out in buffer (detection limit- 0.36 fM) and spiked serum (detection limit- 0.53 fM) within the linear range of 1 µM to 1 fM. The fabricated electrode did not show any non-specific binding with Dengue Virus, West Nile Virus or Yellow Fever Virus NS1-Ag. The electrode also provided a stable rapid response within 30 s when reused up to 4 times, and could be stored at 4 °C up to 3 weeks without substantial variation in output. Hence, the developed electrode has future applications for miniaturisation into a rapid diagnostic device for clinical diagnosis of JEV.