Citric acid based (CQDs/TiO2) nanocomposites against SARS-COV-2: theoretical, photocatalytic and computational studies

Abstract

In the last decade, carbon quantum dots (CQDs), a novel class of carbon-based nanomaterials, have received increasing attention due to their distinct properties. Carbon Quantum Dots/Titanium Dioxide (CQDs/TiO₂) Nanocomposites were reported as potent compounds against SARS-COV-2. In this manuscript, citric acid is the carbon precursor used to synthesize carbon quantum dots (CQDs). Using a green approach, the synthesized CQD fabricates the Carbon Quantum Dots/Titanium Dioxide (CQDs/TiO2) Nanocomposites. Synthesized composites were characterized by using a UV–visible spectrophotometer, Fourier-transformed infrared (FTIR) spectrometry, X-ray diffractometry (XRD), and Scanning electron microscopy with energy dispersive X-ray analysis (SEM–EDX). Methylene blue was used to check the Photocatalytic activity of synthesized (CQDs/TiO₂) nanocomposites of different concentrations. Computational modeling of agglomerates of CQD and TiO2 nanoparticles with the formula TiO₂…….. Ti₂₅₃O₅₀₆ demonstrated two stages of the nanocomposite formation, including the formation of agglomerates with the neutral and salt-like structures with the total gain in the Gibbs free energy − 38.397 kcal/mole. In silico, Molecular docking studies of citric acid were evaluated against SARS-COV-2 protein to understand their mechanism and key amino acid interactions along with standard drug remdesivir. The photocatalytic activity of CQDs/TiO₂ showed extremely promising results. Based on this study, the proposed mechanism of action of these compounds is reported. A detailed investigation of CQDs/TiO₂ against SARS-CoV-2 is needed, which is another part of the research in our next manuscript.