N-Heterocyclic Carbene-Graphene Nanotransistor Based on Covalent Bond for Ultrastable Biosensors

Abstract

Fatal pathogenic organisms have been detected by various point-of-care tests (PoCTs) in clinical samples. PoCTs based on portable electrical devices are able to detect organisms in simple and rapid method. Although electrical PoCT devices show ultra sensitivity when detecting pathogens in standard samples, their industrialization has been limited due to low reproducibility, sensitivity, and specificity, resulting from nonspecific binding issues by media. In this research, a perpendicular N-heterocyclic carbene self-assembled monolayer (NHC-SAM) conjugated on graphene micropattern field-effect transistors (NGMFETs) is first demonstrated for monitoring pathogens. Two single bonds of NHCSAM on GM are investigated via density functional theory (DFT) and surface analyses. Bioreceptors are conjugated on the side gate-modulated NGMFET for ultra-stable on-site detection. The side-gated BNGMFETs system displayed remarkable performance in the detection of the following: i) SARS-CoV-2 spike protein S1 (limit of detection (LOD): approximate to 10 pg mL-1) in CTM, ii) O. tsutsugamushi Ab (LOD: approximate to 1 pg mL-1), and iii) E. coli (LOD: 10 degrees CFU mL-1) in serum. Compared to commercial methodology, the platform presents 102 times higher LODs towards those pathogens in clinical samples with higher reproducibility. Based on these results, side-gated BNGMFETs can be utilized as universal PoCT during pandemics. Interfacial compound, N-heterocyclic carbene, is introduced for the development of an ultrastable biosensor by forming a self-assembly monolayer onto graphene micropatterned field-effect transistor. The bioreceptor-integrated platforms are used for the diagnosis of various organisms such as viruses and bacteria, which shows excellent performances and high specificity including various interference materials. This biosensor platform can be utilized for rapid diagnosis technology in the next pandemic. image