Electrochemical immunosensor with Cu2O nanocube coating for detection of SARS-CoV-2 spike protein

Abstract

Severe acute respiratory syndrome SARS-CoV-2 has caused a global pandemic starting in 2020. Accordingly, testing is crucial for mitigating the economic and public health effects. In order to facilitate point-of-care diagnosis, this study aims at presenting a label-free electrochemical biosensor as a powerful nanobiodevice for SARS-CoV-2 spike protein detection. Utilizing the IgG anti-SARS-CoV-2 spike antibody onto the electrode surface as a specific platform in an ordered orientation through staphylococcal protein A (ProtA) is highly significant in fabricating the designed nanobiodevice. In this sense, the screen-printed carbon electrode modified with Cu 2 O nanocubes (Cu 2 O NCs), which provide a large surface area in a very small space, was applied in order to increase the ProtA loading on the electrode surface. Accordingly, the sensitivity and stability of the sensing platform significantly increased. The electrochemical evaluations proved that there is a very good linear relationship between the charge transfer resistance ( R ct ) and spike protein contents via a specific binding reaction in the range 0.25 fg mL −1 to 1 μg mL −1 . Moreover, the assay when tested with influenza viruses 1 and 2 was performed in 20 min with a low detection limit of 0.04 fg mL −1 for spike protein without any cross-reactivity. The designed nanobiodevice exhibited an average satisfactory recovery rate of ~ 97–103% in different artificial sample matrices, i.e., saliva, artificial nasal, and universal transport medium (UTM), illustrating its high detection performance and practicability. The nanobiodevice was also tested using real patients and healthy samples, where the results had been already obtained using the standard polymerase chain reaction (PCR) procedure, and showed satisfactory results. Graphical abstract Supplementary Information The online version contains supplementary material available at 10.1007/s00604-021-04762-9.

Screen-Printed Graphene/Carbon Electrodes on Paper Substrates as Impedance Sensors for Detection of Coronavirus in Nasopharyngeal Fluid Samples

“…ProtA, a strong immunological instrument, was used in this regard, which can strongly bind to the Fc region of IgG antibodies, leading to well-defined orientations of the antibody elements. In an earlier report [29], this strategy was tested on Cu 2 O modified commercial electrodes with good recognition ability for the spike proteins. In this study, we utilized graphene on paper electrodes using the same strategy.…”

“…Specific examples include a graphene-based field-effect transistor (FET) biosensor [26], a plasmonic photothermal biosensor [27], a fluorescence-based microfluidic immunoassay [28], and a small variety of electrochemical and impedance biosensors using commercial screen-printed electrodes. In one of these reports, the carbon electrodes were functionalized with the Cu 2 O nanocubes to enhance the surface area of the electrode for improving the functionality of the impedance-based mechanism [29]. The sensor explored the same COVID-19 spike protein-spike antibody interaction through another protein mediated immobilization of the antibody.…”

“…With these objectives, we started to explore paper substrates for detection purposes. Among the many sensing mechanisms, electrochemical and impedance transduction is highly suitable due to its good sensitivity, low cost, low response time, and small sample requirement [22,29,31]. More importantly, the amenability to miniaturization, and subsequent portability, through already available devices provides it with immense potential for screening and POC testing.…”

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

“…The generation of an electrochemical signal upon target analyte binding enables the rapid and specific detection of antigens, often at very low concentrations. A number of electrochemical biosensors for SARS-CoV-2 have been developed over the past year [7] , [9] , [10] , [11] , [12] , [13] , [14] , [15] .…”

Development and application of a SARS-CoV-2 colorimetric biosensor based on the peroxidase-mimic activity of γ-Fe2O3 nanoparticles

“…Currently, laborious, time-consuming, and specialized personnel needed realtime polymerase chain reaction (RT-PCR) technique is the gold standard method for SARS-CoV-2 detection. Due to the disadvantages mentioned above, accurate, rapid, and practical methods that have a point of care (POC) nature are urgently needed [14]. Conducting the diagnostic test at home without needing to leave the house and learning the result rapidly, will allow a person to quarantine himself immediately thus preventing the spread of the virus.…”