Nanoparticles improve targeting and efficacy of endocytosis inhibitors

Endocytosis is a critical cellular process exploited by many viruses, including HIV-1 and SARS-CoV-2, for host cell entry. Inhibiting this pathway provides a promising antiviral strategy; however, existing small-molecule inhibitors often suffer from limited solubility, off-target effects, and poor bioavailability. This study reports the synthesis and evaluation of gold nanoparticles functionalized with novel endocytosis inhibitors, Les-6623 and Les-6632. The compounds were synthesized via a linear Knoevenagel condensation pathway and structurally confirmed by NMR and LC-MS spectroscopy. Molecular docking predicted more favorable interactions of Les-6623 and Les-6632 with dynamin-2 than those predicted for chlorpromazine, a classical endocytosis inhibitor. PEGylated gold nanoparticles were functionalized with the inhibitors, yielding formulations characterized by UV-Vis, fluorescence spectroscopy, ATR-FTIR, DLS, and TEM analyses. Functional assays in SH-SY5Y and BEAS-2B cells showed that AuNP_Les-6623 and AuNP_Les-6632 reduced the cellular fluorescence associated with transferrin, HIV-1 Tat, and SARS-CoV-2 Spike protein under the experimental conditions tested. Free chlorpromazine was included as a reference inhibitor. These findings support the biological activity of the investigated nanoparticle formulations under the tested conditions, while further format-matched controls are required to determine the specific contribution of nanoparticle presentation to the observed activity.