Label-free electrochemical aptasensor for the detection of SARS-CoV-2 spike protein based on carbon cloth sputtered gold nanoparticles

Muhammad Adeel; Kanwal Asif; Fahad Alshabouna; Vincenzo Canzonieri; Md Mahbubur Rahman; Sajid Ali Ansari; Firat Güder; Flavio Rizzolio; Salvatore Daniele

doi:10.1016/j.biosx.2022.100256

Label-free electrochemical aptasensor for the detection of SARS-CoV-2 spike protein based on carbon cloth sputtered gold nanoparticles

Biosens Bioelectron X. 2022 Dec:12:100256. doi: 10.1016/j.biosx.2022.100256. Epub 2022 Sep 24.

Authors

Muhammad Adeel^{1

2

3}, Kanwal Asif^{1

2}, Fahad Alshabouna^{3

4}, Vincenzo Canzonieri^{2

5}, Md Mahbubur Rahman⁶, Sajid Ali Ansari⁷, Firat Güder³, Flavio Rizzolio^{1

2}, Salvatore Daniele¹

Affiliations

¹ Department of Molecular Sciences and Nanosystems, Ca'Foscari University of Venice, 30123, Venezia, Italy.
² Pathology Unit, Centro di Riferimento Oncologico di Aviano (CRO) IRCCS, 33081, Aviano, Italy.
³ Department of Bioengineering, Imperial College London, London, SW7 2AZ, UK.
⁴ Center of Excellence for Advanced Materials and Manufacturing, King Abdulaziz City for Science and Technology, 11442, Riyadh, Saudi Arabia.
⁵ Department of Medical, Surgical and Health Sciences, University of Trieste, 34127, Trieste, Italy.
⁶ Department of Applied Chemistry, Konkuk University, Chungju, 27478, South Korea.
⁷ Department of Physics, College of Science, King Faisal University, P. O. Box 400, Hofuf, Al-Ahsa, 31982, Saudi Arabia.

Abstract

The proliferation and transmission of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), or the (COVID-19) disease, has become a threat to worldwide biosecurity. Therefore, early diagnosis of COVID-19 is crucial to combat the ongoing infection spread. In this study we propose a flexible aptamer-based electrochemical sensor for the rapid, label-free detection of SARS-CoV-2 spike protein (SP). A platform made of a porous and flexible carbon cloth, coated with gold nanoparticles, to increase the conductivity and electrochemical performance of the material, was assembled with a thiol functionalized DNA aptamer via S-Au bonds, for the selective recognition of the SARS-CoV-2 SP. The various steps for the sensor preparation were followed by using scanning electron microscopy, cyclic voltammetry and differential pulse voltammetry (DPV). The proposed platform displayed good mechanical stability, revealing negligible changes on voltammetric responses to bending at various angles. Quantification of SARS-CoV-2 SP was performed by DPV and chronopotentiometry (CP), exploiting the changes of the electrical signals due the [Fe(CN)₆]^3-/4- redox probe, when SARS-CoV-2 SP binds to the aptamer immobilized on the electrode surface. Current density, in DPV, and square root of the transition time, in CP, varied linearly with the log[ SARS-CoV-2 SP], providing lower limits of detection (LOD) of 0.11 ng/mL and 37.8 ng/mL, respectively. The sensor displayed good selectivity, repeatability, and was tested in diluted human saliva, spiked with different SARS-CoV-2 SP concentrations, providing LODs of 0.167 ng/mL and 46.2 ng/mL for DPV and CP, respectively.

Keywords: Aptamers; COVID-19; Diagnostics; Electrochemical sensing; Flexible carbon cloth; Spike protein.