Electrochemical and spectrophotometric investigation of DNA interactions with TURKOVAC and Pfizer-BioNTech vaccines: Implications for biosensor sensitivity.

BACKGROUND

The novel coronavirus disease (COVID-19), caused by the SARS-CoV-2 virus, has led to the rapid development of several vaccines, including TURKOVAC and Pfizer-BioNTech. Understanding their electrochemical behavior and interactions with biological macromolecules is crucial for vaccine safety and efficacy evaluation. In this context, a simple, cost-effective, and sensitive electrochemical bio sensing platform was designed using differential pulse voltammetry (DPV) on a disposable pencil graphite electrode. The proposed sensor enables rapid electroanalytical characterization of vaccine formulations and provides a green analytical approach suitable for biological and pharmaceutical investigations.

RESULTS

The disposable pencil graphite electrode demonstrated distinct anodic oxidation peaks at +0.90 V and +0.92 V for TURKOVAC and Pfizer-BioNTech vaccines, respectively, in Britton-Robinson buffer at pH 4.0. Surface characterization was carried out using cyclic voltammetry, electrochemical impedance spectroscopy, and scanning electron microscopy, confirming successful sensor performance and reproducibility. Under optimized experimental conditions, DNA interaction studies were performed by DPV, revealing marked shifts in oxidation signals upon complex formation with both vaccines. Complementary UV-Visible spectrophotometric analyses confirmed these findings, indicating consistent and thermodynamically stable vaccine-DNA binding. The combined results validated the sensor's high sensitivity, reliability, and applicability in real biological samples.

SIGNIFICANCE: This study demonstrates the first use of a disposable pencil graphite electrode for simultaneous electrochemical and spectrophotometric investigation of SARS-CoV-2 vaccines and their DNA interactions. The developed platform offers a green, sustainable, and disposable analytical approach with potential applications in vaccine quality control, biosensor development, and molecular-level understanding of vaccine-biomolecule interactions essential for future vaccine design strategies.