Adsorption Potential of Ag Nanoparticles with Azvudine (FNC) Investigated by Density Functional Theory and Raman Spectroscopy

Azvudine (FNC) is a dual-target inhibitor of HIV reverse transcriptase and accessory protein Vif, which can effectively inhibit the reverse transcription and replication of the HIV virus in vivo and can also be used for the treatment of novel coronavirus infection. In this article, density functional theory (DFT) combined with surface-enhanced Raman spectroscopy (SERS) is used for the first time to study the interaction between FNC and Ag nanoparticles. In order to predict the potential binding sites of FNC and Ag nanoparticles (AgNPs) of the SERS effect, the geometric configuration of FNC molecules is optimized by the B3LYP-D3/6-311++G(d,p) method, and the natural bond orbital (NBO) properties, molecular electrostatic potential (MEP), Frontier molecular orbitals (FMOs), and molecular polarizability of FNC molecules are studied. The study of the SERS chemical enhancement mechanism of FNC at different adsorption sites of the Ag 6 nanocluster confirmed that there is charge transfer between the FNC molecule and the Ag 6 nanocluster, which can adsorb and form stable FNC–Ag 6 complexes. Subsequently, the Raman spectra of FNC and the FNC–Ag 6 complex are compared and analyzed, and the adsorption conformation of FNC on the silver surface is determined based on the SERS surface selection rule. The results provide a theoretical basis for exploring the mechanism of chemical enhancement between FNC and Ag nanoparticles.