A Folding-Based Electrochemical Aptasensor for the Single-Step Detection of the SARS-CoV-2 Spike Protein

Abstract

Efficient and timely testing has taken center stage in the management, control, and monitoring of the current COVID-19 pandemic. Simple, rapid, cost-effective diagnostics are needed that can complement current polymerase chain reaction-based methods and lateral flow immunoassays. Here, we report the development of an electrochemical sensing platform based on single-walled carbon nanotube screen-printed electrodes (SWCNT-SPEs) functionalized with a redox-tagged DNA aptamer that specifically binds to the receptor binding domain of the SARS-CoV-2 spike protein S1 subunit. Single-step, reagentless detection of the S1 protein is achieved through a binding-induced, concentration-dependent folding of the DNA aptamer that reduces the efficiency of the electron transfer process between the redox tag and the electrode surface and causes a suppression of the resulting amperometric signal. This aptasensor is specific for the target S1 protein with a dissociation constant ( K D ) value of 43 ± 4 nM and a limit of detection of 7 nM. We demonstrate that the target S1 protein can be detected both in a buffer solution and in an artificial viral transport medium widely used for the collection of nasopharyngeal swabs, and that no cross-reactivity is observed in the presence of different, non-target viral proteins. We expect that this SWCNT-SPE-based format of electrochemical aptasensor will prove useful for the detection of other protein targets for which nucleic acid aptamer ligands are made available.

Progress in Electrochemical Biosensing of SARS-CoV-2 Virus for COVID-19 Management

“…The aptasensor could detect the picomolar level of SP with high specificity. In another report, Curti et al reported another label-based aptasensor based on single-walled carbon nanotube screen-printed electrodes (SWCNT-SPEs) functionalized with a redox-tagged DNA aptamer [73]. The selective binding of SARS-CoV-2 SP folded the DNA aptamer which reduces the efficiency of the electron transfer between the AttoMB2 redox label and the electrode surface.…”

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

“… Abrego-Martinez et al, 2022 ; Amouzadeh Tabrizi et al, 2021 ; Curti et al, 2022 ; Farrow et al, 2020 ; Jiang et al, 2021 ; Kurnia Sari et al, 2022 ; Lasserre et al, 2022 ; Singh et al, 2021 ; Tian et al, 2021 ; Zakashansky et al, 2021 .…”

Recent Progresses in Electrochemical DNA Biosensors for SARS-CoV-2 Detection

“…The adapted ssDNA can block virus infection in vitro. It is possible to prepare multifunctional sensors (Curti et al, 2022). Designing a highly sensitive assay is urgent for the early diagnosis and treatment of SARS-CoV-2.…”