Graphene-Binding Peptide in Fusion with SARS-CoV-2 Antigen for Electrochemical Immunosensor Construction

Abstract

The development of immunosensors to detect antibodies or antigens has stood out in the face of traditional methods for diagnosing emerging diseases such as the one caused by the SARS-CoV-2 virus. The present study reports the construction of a simplified electrochemical immunosensor using a graphene-binding peptide applied as a recognition site to detect SARS-CoV-2 antibodies. A screen-printed electrode was used for sensor preparation by adding a solution of peptide and reduced graphene oxide (rGO). The peptide-rGO suspension was characterized by scanning electron microscopy (SEM), Raman spectroscopy, and Fourier transform infrared spectroscopy (FT-IR). The electrochemical characterization (electrochemical impedance spectroscopy—EIS, cyclic voltammetry—CV and differential pulse voltammetry—DPV) was performed on the modified electrode. The immunosensor response is based on the decrease in the faradaic signal of an electrochemical probe resulting from immunocomplex formation. Using the best set of experimental conditions, the analytic curve obtained showed a good linear regression (r2 = 0.913) and a limit of detection (LOD) of 0.77 μg mL−1 for antibody detection. The CV and EIS results proved the efficiency of device assembly. The high selectivity of the platform, which can be attributed to the peptide, was demonstrated by the decrease in the current percentage for samples with antibody against the SARS-CoV-2 S protein and the increase in the other antibodies tested. Additionally, the DPV measurements showed a clearly distinguishable response in assays against human serum samples, with sera with a response above 95% being considered negative, whereas responses below this value were considered positive. The diagnostic platform developed with specific peptides is promising and has the potential for application in the diagnosis of other infections that lead to high antibody titers.

An Advanced Healthcare Sensing Platform for Direct Detection of Viral Proteins in Seconds at Femtomolar Concentrations via Aerosol Jet 3D‐Printed Nano and Biomaterials

“…Table 1 shows the sensing performance of the 3D microelectrode‐based biosensing platform when compared to reported literature for the SARS‐CoV‐2 spike protein. An analogous limit‐of‐detection was seen with the conventional sensing materials such as screen printed electrodes, [ 43 ] rGO coated screen printed electrode, [ 44 ] laser‐script graphene, [ 34d ] titanium dioxide nanotube [ 45 ] and paper‐based [ 46 ] sensing platforms (see Table 1). A faster detection system (30 s) for COVID‐19 was realized when the titanium dioxide nanotube [ 45 ] was used as a sensing material for the detection of antigen.…”

“…However, their limit‐of‐detection and analytical sensitivity (0.07–14 n m ) of the target analyte are moderate. [ 45 ] When the rGO sheets were coated on a planar screen printed electrode, [ 44 ] the sensor showed a detectivity within a range of 1–60 n m , an LoD of 10 n m and a detection of time of 60 min. Our 3D sensor exhibits an excellent sensing performance such as it shows a detection time of 43 s and an LoD of 9.2 f m due to the 3D micropillar array of rGO‐Au electrodes.…”

“…Laser-scribed graphene [ 34d] Pulse voltammetry 38.6 fm 66.6 fm 66.6 fm-6.6 pm 60 min Screen-printed carbon electrode [ 47] Square wave voltammogram 8.5 fm 21.2 fm 21.2 fm-2.1 pm 15 min rGO-modified screen-printed carbon electrode [ 44] Pulse voltammetry 10 nm 1 nm 1-60 nm 60 min…”

Graphene-Based Electrochemical Nano-Biosensors for Detection of SARS-CoV-2

“…A facile electrochemical biosensor was developed by Braz et al [74] using a peptide that binds to graphene as the recognition site for detecting antibodies against SARS-CoV-2. The sensor was fabricated by applying a solution of the peptide and rGO to an SPE.…”

Clinically Deployable Bioelectronic Sensing Platform for Ultrasensitive Detection of Transferrin in Serum Sample

“…Wang et al developed an electrochemical nanosensor based on a nanocomposite of rGO, polyethyleneimine, silver nanoparticles, and nafion to detect arsanilic acid (ASA) [ 23 ]. Braz et al used a graphene–solid binding peptide to detect SARS-CoV 2 antibodies [ 24 ]. Ketmen et al fabricated GO–magnetic nanoparticles on polystyrene–polydopamine electrospun nanofibers for the electrochemical sensing of C-reactive protein (CRP) [ 25 ].…”