Graphene functionalized field-effect transistors for ultrasensitive detection of Japanese encephalitis and Avian influenza virus

Abstract

Graphene, a two-dimensional nanomaterial, has gained immense interest in biosensing applications due to its large surface-to-volume ratio, and excellent electrical properties. Herein, a compact and user-friendly graphene field effect transistor (GraFET) based ultrasensitive biosensor has been developed for detecting Japanese Encephalitis Virus (JEV) and Avian Influenza Virus (AIV). The novel sensing platform comprised of carboxy functionalized graphene on Si/SiO 2 substrate for covalent immobilization of monoclonal antibodies of JEV and AIV. The bioconjugation and fabrication process of GraFET was characterized by various biophysical techniques such as Ultraviolet-Visible (UV-Vis), Raman, Fourier-Transform Infrared (FT-IR) spectroscopy, optical microscopy, Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). The change in the resistance due to antigenantibody interaction was monitored in real time to evaluate the electrical response of the sensors. The sensors were tested in the range of 1 fM to 1 μM for both JEV and AIV antigens, and showed a limit of detection (LOD) upto 1 fM and 10 fM for JEV and AIV respectively under optimised conditions. Along with ease of fabrication, the GraFET devices were highly sensitive, specific, reproducible, and capable of detecting ultralow levels of JEV and AIV antigen. Moreover, these devices can be easily integrated into miniaturized FET-based real-time sensors for the rapid, cost-effective, and early Point of Care (PoC) diagnosis of JEV and AIV. The development of Point of Care (PoC) disease detection kits providing ultra-sensitive, selective, and rapid advances in recent times. In this article, we have focused on graphene-based biosensors for the detection of two different viruses by detecting their respective viral antigen i.e. Japanese encephalitis virus (JEV) and Avian Influenza Virus (AIV). JEV belongs to the family Flaviviridae genus Flavivirus 1 and exists in a zoonotic cycle between the vector i.e. Culex mosquitos, while humans are the dead end host due to low and short-lived viremia of JEV 2-5. Most infections of JEV are asymptomatic, however, the case-fatality rate among those with encephalitis can be as high as 30%, or more in children. It causes clinical symptoms in humans, including a non-specific febrile illness, meningitis, encephalitis and meningo-encephalitis. Pigs play an important role and serve as an amplifier and have a natural infection rate of 98-100% 6. As JEV is incurable and the vaccination is not full-proof, an early diagnosis is critical in preventing an epidemic outbreak, especially since the initial symptoms are usually mistaken for dengue or malaria. The conventional diagnostic methods for JEV 7 such as Enzyme-Linked Immunosorbent Assays (ELISA) 8 ,

Emerging Biosensors to Detect Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2): A Review

“…In addition, two-dimensional materials such as graphene are widely used in SPR, FET and electrochemical based biosensors. The high surface area to volume ratio and carbon-based ring structures of graphene enhances the adsorption of biorecognition elements onto the sensor surface [ 147 , 148 ]. Adding graphene-based materials on the gold film of SPR sensors allow detection down to fg/mL of mass change [ 149 ].…”

“…Graphene and reduced graphene oxide possess excellent electronic properties, which allow them to be used as sensor surface material in FET [ 150 ] and electrochemical sensors [ 151 ]. Due to the excellent electronic and adsorption properties of these materials, the LOD of the FET biosensor reported in [ 147 ] is 1 fM and 10 fM for the detection of the Japanese encephalitis and avian influenza virus, respectively. However, graphene yields a small current on-off ratio in FETs, which limits its sensitivity [ 136 ].…”

Emerging materials for the electrochemical detection of COVID-19

“…Another type of biosensors for the detection of viruses are the field effect transistors (FET), in which the last few years graphene was adopted as the active material [113] , [114] , [115] . Recently, a promising electrochemical FET SARS-CoV-2 biosensor, applying graphene sheets as sensing material, was fabricated by Seo et al [104] .…”

Label-free detection of SARS-CoV-2 Spike S1 antigen triggered by electroactive gold nanoparticles on antibody coated fluorine-doped tin oxide (FTO) electrode

“…Biosensors are sensitive, specific, stable, easy to use, require less sample size, time, portable and most importantly can be customised to detect the target analyte of interest. Immunosensors can be used to detect toxins [ 25 ], narcotic drugs [ [26] , [27] , [28] , [29] ], viruses [ [30] , [31] , [32] ] by use of different bioreceptors such as deoxyribonucleic acid (DNA) [ 33 , 34 ], enzymes [ 35 , 36 ], peptides [ 37 ], aptamers [ 38 ], antibody [ 39 , 40 ]. Electrochemical biosensors are considered as a reliable tool for infectious disease detection as they remain unaffected by sample absorbance or turbidity [ 41 ].…”