Graphene on SiC Substrate as Biosensor: Theoretical Background, Preparation, and Characterization

Abstract

This work is devoted to the development and optimization of the parameters of graphene-based sensors. The graphene films used in the present study were grown on semi-insulating 6H-SiC substrates by thermal decomposition of SiC at the temperature of ~1700 °C. The results of measurements by Auger and Raman spectroscopies confirmed the presence of single-layer graphene on the silicon carbide surface. Model approach to the theory of adsorption on epitaxial graphene is presented. It is demonstrated that the Green-function method in conjunction with the simple substrate models permit one to obtain analytical results for the charge transfer between adsorbed molecules and substrate. The sensor structure was formed on the graphene film by laser. Initially, a simpler gas sensor was made. The sensors developed in this study demonstrated sensitivity to the NO2 concentration at the level of 1–0.01 ppb. The results obtained in the course of development and the results of testing of the graphene-based sensor for detection of protein molecules are also presented. The biosensor was fabricated by the technology previously developed for the gas sensor. The working capacity of the biosensor was tested with an immunochemical system constituted by fluorescein and monoclonal antibodies (mAbs) binding this dye.

Investigation of the Morphology and Electrical Properties of Graphene Used in the Development of Biosensors for Detection of Influenza Viruses

“…The fabrication of such biosensors would make it possible to find out the mechanism of the spread of COVID-19. Recent reports have proposed graphene as a prospective material for these biosensors [ 1 , 2 , 3 , 4 , 5 , 6 ] thanks to its unusual physical properties, which are different from sensors’ 3D bulk counterparts. Graphene is a two-dimensional single atomic layer of sp 2 bonded carbon atoms arranged in a honeycomb lattice.…”

“…When it comes to the registration of influenza viruses and the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that causes COVID-19, several reports have shown the great promise of the application of chips based on graphene films with two contacts, i.e., graphene resistances [ 1 , 2 ]. The main stages of creating biosensors for the influenza and SARS-CoV-2 viruses are similar.…”

“…Significant improvements in the detection of low concentration of influenza viruses and COVID-19 by graphene biosensors have been achieved recently. Some works [ 1 , 2 , 7 ] report the detection of a viral concentration of ~1 fg/mL, which is comparable or below the detectable limits of modern laboratory methods of enzyme-linked immunosorbent assay. However, solving the above-mentioned practical tasks requires the high reproducibility of viral detection.…”

“…The commonly accepted concept of viral biosensor production is based on the creation of conditions for the antibody–antigen (virus) immune reaction on a graphene surface. It can include controlled treatment (functionalization) of the graphene surface to create covalent bonds that ensure the occurrence of selective chemical reactions of the attachment of biomolecules (antibodies) [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 ]. The antibody–antigen immune reaction on the graphene surface changes its electronic state, which can be registered, for example, by a change in the current flowing through a graphene chip.…”

Special Issue: Silicon Carbide: From Fundamentals to Applications

“…Possible applications of SiC substrates to obtain graphene sensors for biological applications are described in Reference [6]. The authors of this work grew graphene films on a semi-insulating 6H-SiC substrate by thermal decomposition at a temperature of 1700 • C. Note that the method of thermal destruction of the silicon carbide surface makes it possible to obtain graphene films with a sufficiently high structural perfection.…”