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. 2022 Aug:146:108106.
doi: 10.1016/j.bioelechem.2022.108106. Epub 2022 Mar 23.

Label-free electrochemical aptasensor for rapid detection of SARS-CoV-2 spike glycoprotein based on the composite of Cu(OH)2 nanorods arrays as a high-performance surface substrate

Zeinab Rahmati  1 , Mahmoud Roushani  2 , Hadi Hosseini  1 , Hamzeh Choobin  3
Affiliations

Label-free electrochemical aptasensor for rapid detection of SARS-CoV-2 spike glycoprotein based on the composite of Cu(OH)2 nanorods arrays as a high-performance surface substrate

Zeinab Rahmati et al. Bioelectrochemistry. 2022 Aug.

Abstract

The development of advanced electrode materials and the combination of aptamer with them have improved dramatically the performance of aptasensors. Herein, a new architecture based on copper hydroxide nanorods (Cu(OH)2 NRs) are directly grown on the surface of screen printed carbon electrode (SPCE) using a two-step in situ, very simple and fast strategy and was used as a high-performance substrate for immobilization of aptamer strings, as well as an electrochemical probe to development a label-free electrochemical aptasensor for SARS-CoV-2 spike glycoprotein measurement. The Cu(OH)2 NRs was characterized using X-ray Diffraction (XRD) and electron microscopy (FESEM). In the presence of SARS-CoV-2 spike glycoprotein, a decrease in Cu(OH)2 NRs-associated peak current was observed that can be owing to the target-aptamer complexes formation and thus blocking the electron transfer of Cu(OH)2 NRs on the surface of electrode. This strategy exhibited wide dynamic range in of 0.1 fg mL-1 to 1.2 µg mL-1 and with a high sensitivity of 1974.43 μA mM-1 cm-2 and low detection limit of 0.03 ± 0.01 fg mL-1 of SARS-CoV-2 spike glycoprotein deprived of any cross-reactivity in the presence of possible interference species. In addition, the good reproducibility, repeatability, high stability and excellent feasibility in real samples of saliva and viral transport medium (VTM) were found from the provided aptasensor. Also, the aptasensor efficiency was evaluated by real samples of sick and healthy individuals and compared with the standard polymerase chain reaction (PCR) method and acceptable results were observed.

Keywords: Aptamer-based sensors; COVID-19; Copper hydroxide nanorods; SARS-CoV-2; Spike glycoprotein.

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Conflict of interest statement

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Figures

None
Graphical abstract
Scheme 1
Scheme 1
Schematic illustration of the steps of the aptasensor preparation.
Fig. 1
Fig. 1
The FESEM images of Cu@SPCE (a-c), EDX spectrum (d) and EDS mapping of Cu@SPCE (e-g).
Fig. 2
Fig. 2
The FESEM images of Cu(OH)2 NRs@SPCE (a-c), EDX spectrum (d) and EDS mapping of Cu(OH)2 NRs@SPCE (e-h).
Fig. 3
Fig. 3
The XRD patterns of as-prepared Cu(OH)2 NRs.
Fig. 4
Fig. 4
The FTIR spectrums of (a) aptamer, (b) as-prepared Cu(OH)2 NRs, and (c) aptamer/Cu(OH)2 NRs.
Fig. 5
Fig. 5
(A) SWV characterization of different modified electrodes in PBS with pH = 7.4 and (B) EIS characterization in PBS with pH = 7.4 containing K3Fe(CN)6/ K4Fe(CN)6 (5 mM) in a 1 to 1 ratio: (a) SPCE, (b) Cu(OH)2 NRs@SPCE, (c) Apt/Cu(OH)2 NRs@SPCE, (d) BSA/Apt/Cu(OH)2 NRs@SPCE and (e) SARS-CoV-2 spike glycoprotein/BSA/Apt/ Cu(OH)2 NRs@SPCE, inset B: the obtained equivalent circuit. (C) The SWV response of the provided aptasensor after incubating with different concentrations of the SARS-CoV-2 spike glycoprotein solutions in range of 0.1 fg mL−1 to 1.2 µg mL−1 (n = 3) in PBS with pH = 7.4. (D) Calibration curve of Cu(OH)2 NRs-associated cathodic peak current of related to aptasensor vs log C SARS-CoV-2 spike glycoprotein (fg mL−1). The regression equation was ΔI (µA) = −5.5284 log C (fg mL−1) – 17.319 (R2 = 0.9979).
Fig. 6
Fig. 6
(A) SWV response in PBS pH = 7.4 and histogram of then aptasensor after incubation with influenza A H1N1, influenza A H3N2, SARS-CoV, MERS-CoV and blank.
See this image and copyright information in PMC

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