Boron doped diamond thin films for the electrochemical detection of SARS-CoV-2 S1 protein

Abstract

Amidst a global pandemic, a precise and widely accessible rapid detection method is needed for accurate diagnosis and contact tracing. The lack of this technology was exposed through the outbreak of SARS-CoV-2 beginning in 2019. This study sets the foundation for the development of a boron doped diamond (BDD)-based impedimetric sensor. While specifically developed for use in the detection of SARS-CoV-2, this technology uses principles that could be adapted to detect other viruses in the future. Boron doped polycrystalline diamond electrodes were functionalized with a biotin-streptavidin linker complex and biotinylated anti-SARS-CoV-2 S1 antibodies. Electrodes were then incubated with the S1 subunit of the SARS-CoV-2 spike surface protein, and an electrical response was recorded using the changes to the electrode's charge transfer resistance (R ct ), measured through electrochemical impedance spectroscopy (EIS). Detectable changes in the R ct were observed after 5-min incubation periods with S1 subunit concentrations as low as 1 fg/mL. Incubation with Influenza-B Hemagglutinin protein resulted in minimal change to the R ct , indicating specificity of the BDD electrode for the S1 subunit of SARS-CoV-2. Detection of the S1 subunit in a complex (cell culture) medium was also demonstrated by modifying the EIS protocol to minimize the effects of sample matrix binding. BDD films of varying surface morphologies were investigated, and material characterization was used to give insight into the microstructure-performance relationship of the BDD sensing surface.

Peptide-based simple detection of SARS-CoV-2 with electrochemical readout

“…Previous reports have found that Electrochemical Impedance Spectroscopy (EIS)-based biosensors rapidly detect bioreceptors associated with SARS-CoV-2 infection, with high sensitivity, specificity and reliability [ [8] , [9] , [10] , [11] , [12] , [13] , [14] , [15] , [16] , [17] ]. In such biosensors, bioreceptors are anchored on the working electrode surface to directly bind to target molecules specifically, generating changes in the interfacial properties in a concentration-dependent manner [ [18] , [19] , [20] ].…”

Impedimetric Detection Based on Label-Free Immunoassay Developed for Targeting Spike S1 Protein of SARS-CoV-2

“…In contrast to earlier work [ 5 ], there is no need to use a secondary antibody in applying the label-free immunoassay, since our assay was mainly based on direct interaction of the antibody with its target without applying any extra intermediaries. Moreover, no surface modification using other molecules such as protein A [ 6 ] or biotin [ 37 ] on the electrode surface was applied in our study. Overall, the surface treatment/functionalization of the immunosensor was achieved herein straightforwardly and faster than for previous approaches using the indium tin oxide (ITO) electrode [ 10 , 28 ] and the boron-doped polycrystalline diamond electrode [ 37 ].…”

“…Some earlier studies have been conducted regarding the implementation of EIS technique in the detection of SARS-CoV-2 [ 6 , 7 , 10 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 ]. For instance, Rahmati et al [ 6 ] modified the surfaces of disposable SPCEs with Cu 2 O nanocubes and immobilized Protein A onto the modified electrode surface.…”

“…After the immobilization step, SARS-CoV-2 virus detection was explored by EIS technique. Streptavidin-modified boron-doped polycrystalline diamond electrodes were developed for the immobilization of biotin-labeled SARS-CoV-2 S1 antibodies and then applied for impedimetric detection of the SARS-CoV-2 S1 protein [ 37 ]. However, the procedure was similar to the most of earlier reports on impedimetric immunosensors, with the authors following a time-consuming procedure for the development of the immunosensor, while using expensive and laborious electrodes.…”

Performance of electrochemical immunoassays for clinical diagnostics of SARS-CoV-2 based on selective nucleocapsid N protein detection: Boron-doped diamond, gold and glassy carbon evaluation

“…Moreover, the electrode-tethered sensors using chronoamperometry were applied to detect viral particles by the kinetic response of the complexation state of the antibody ( Yousefi et al, 2021 ). Recent approaches for immunosensor detection of SARS-CoV-2 were based on spike protein ( Witt et al, 2021 ). Mahari et al (2020) and Perdomo et al (2021) developed in-house built devices using bio-modified screen-printed carbon electrodes (SPCE) with immobilized monoclonal antibodies recognizing spike protein.…”