A Portable and Disposable Electrochemical Sensor Utilizing Laser-Scribed Graphene for Rapid SARS-CoV-2 Detection

Area of Science:

• Biomedical Engineering
• Nanotechnology
• Analytical Chemistry

Background:

• The COVID-19 pandemic necessitated rapid and accurate diagnostic tools.
• Quantitative reverse transcription polymerase chain reaction (RT-qPCR) is sensitive but time-consuming.
• Rapid antigen tests (RATs) offer speed but suffer from lower sensitivity and false negatives.

Purpose of the Study:

• To develop a disposable, electrochemical biosensor for sensitive and specific detection of SARS-CoV-2.
• To utilize a laser-scribed graphene (LSG) platform with a novel immobilization strategy.
• To improve upon the limitations of existing COVID-19 diagnostic methods.

Main Methods:

• Development of LSG-based biosensor strips.
• Employing a split-ester bond ligase system (EsterLigase) for nanobody immobilization.
• Using an anti-spike VHH E nanobody as the probe for the spike receptor-binding domain (SP-RBD).
• Measuring target recognition via electrochemical impedance spectroscopy (EIS).

Main Results:

• Achieved a linear detection range for SP-RBD from 150 pM to 15 nM.
• Demonstrated a sensitivity of 0.0866 [log(M)]^-1.
• Obtained a limit of detection (LOD) of 7.68 pM.

Conclusions:

• The developed LSG-based biosensor offers a promising approach for sensitive COVID-19 detection.
• The EsterLigase system facilitates effective nanobody orientation for enhanced probe-target recognition.
• This technology has the potential for rapid, point-of-care diagnostics.