Clinical Utility of Biosensing Platforms for Confirmation of SARS-CoV-2 Infection

Abstract

Despite collaborative efforts from all countries, coronavirus disease 2019 (COVID-19) pandemic has been continuing to spread globally, forcing the world into social distancing period, making a special challenge for public healthcare system. Before vaccine widely available, the best approach to manage severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is to achieve highest diagnostic accuracy by improving biosensor efficacy. For SARS-CoV-2 diagnostics, intensive attempts have been made by many scientists to ameliorate the drawback of current biosensors of SARS-CoV-2 in clinical diagnosis to offer benefits related to platform proposal, systematic analytical methods, system combination, and miniaturization. This review assesses ongoing research efforts aimed at developing integrated diagnostic tools to detect RNA viruses and their biomarkers for clinical diagnostics of SARS-CoV-2 infection and further highlights promising technology for SARS-CoV-2 specific diagnosis. The comparisons of SARS-CoV-2 biomarkers as well as their applicable biosensors in the field of clinical diagnosis were summarized to give scientists an advantage to develop superior diagnostic platforms. Furthermore, this review describes the prospects for this rapidly growing field of diagnostic research, raising further interest in analytical technology and strategic plan for future pandemics.

Keywords: COVID-19 clinical diagnostics; ELISA; RT-LAMP; RT-PCR; SARS-CoV-2; electrochemical biosensor; lab-in-a-tube; lateral flow assay; nucleic acid amplification; optical biosensor.

Figure 1

Structural models of SARS-CoV-2 and its developed diagnostic platforms. The subgenomic RNAs of the genome encode the following four main structural proteins: Spike protein (S), Envelope small membrane protein (E), nucleocapsid protein (N), and membrane protein (M), as well as several accessory proteins. Schematic representation of an ideal sensing platform composed of nucleic acid amplification technique, optical, and electrochemical sensing platforms. The general configuration of the different sensing platforms for SARS-CoV-2 detection is illustrated.

Figure 2

Colorimetric RT-LAMP and LAMP sequencing for the clinical detection of SARS-CoV-2 RNA. (A) The oligonucleotide set for the nucleocapsid (N) gene of SARS-CoV-2 was added to the RT-LAMP reaction and incubated at 65 °C. The colors of samples changed from red-to-yellow and the negative control was yellowish. (B) Gel electrophoresis showed RT-LAMP reaction products with distinct banding patterns. (C) For clinical pharyngeal swab samples, the direct swab-to-RT-LAMP assay measurements or after 5 min of heat treatment at 95 °C were compared for their ΔOD values from the swab-to-RT-LAMP assay and CT values from the RT-qPCR assay. (D) The sensitivity and specificity of the swab-to-RT-LAMP assay were revealed with their 95% confidence intervals, with the direct swab-to-RT-LAMP assay (blue color) and the heated swab-to-RT-LAMP assay (red color). Reprinted with permission from [41]. Sci. Transl. Med. 2020, 12, 556, eabc7075. Copyright 2020, American Association for the Advancement of Science.

Figure 3

Point-of-care half-strip lateral flow assay for the detection of the nucleocapsid antigen of SARS-CoV-2. (A) The 4 mm width half-strip was constructed using a 20 mm nitrocellulose analytical membrane, 20 mm wicking pad by using a Kinematic Matrix guillotine cutter. (B) LFA was treated in buffer and color intensity of test zone was differentiated after 20 min. (C) The dosage response curve for half-band LFA using nucleocapsid proteins from two commercially available sources, measured with commercially available optical LFA readers. Reprinted with permission from [45]. Anal. Chem. 2020, 92, 16, 11305–11309. Copyright 2020, American Chemical Society.

Figure 4

Rapid agglutination assays as serological testing for the detection of antibodies against SARS-CoV-2. (A) Schematic illustration of blood typing column agglutination test (CAT) with the brief antibody-peptide bioconjugates to produce the SARS-CoV-2 serological assay. (a) Pipette a mixture of reagent red blood cells (RRBCs) with patient samples onto a gel card containing separation media, followed by incubation of the card for 5–15 min. (b) The bioconjugation procedure to produce the antibody-peptide in two steps. (c) Antibody-peptide-coated RRBCs were incubated with a patient sample on a neutral gel prior to centrifugation to separate agglutinated RRBCs from free RRBCs for visual examination. Following optimization of the gel card assays to distinguish between SARS-CoV-2-positive samples and negative controls, 10 clinical samples were tested in both gel cards and by indirect IgG ELISA. (B) The results of indirect IgG ELISA comparing 10 samples, including PCR-confirmed SARS-CoV-2-positive samples and samples from healthy individuals collected before the SARS-CoV-2 outbreak. (C) Digital images of gel card assays recorded from experiments could identify positive/negative of antibodies, negative control noted (“N”). Reprinted with permission from [62]. ACS Sens. 2020, 5, 8, 2596–2603. Copyright 2020, American Chemical Society.

Figure 5

Ultra-rapid electrochemical immunosensor using aerosol jet nanoprinted reduced graphene oxide-coated 3D electrode for the detection of antibodies against SARS-CoV-2. (A) Functionalization of the 3D electrode and sensing operation. (a) AJ-printed gold micropillars prior to the surface treatment. (b) Coating rGO sheets onto the electrodes. (c) Immobilization of viral antigens onto rGO sheets. (d) Selective binding of antibody with specific antigens after introduction. (e) Schematics showing the sensing principle of the 3DcC device. (f) Schematic illustration of the Nyquist plot alternation via electrical impedance spectroscopy (EIS) before and after antibody introduction and binding with the antigens on the electrode surface. (B) The connection of the 3DcC device interfaced with a portable potentiostat to a smartphone via a USB-C connection for signal recording. (C) Sensing performance of antibodies against SARS-CoV-2 spike S1 antigen at different molar concentrations from 1 fM to 20 nM in (a) PBS solution and (b) after sensor regeneration using low-pH chemistry. Reprinted with permission from [65].