A novel nanocomposite drug delivery system for SARS-CoV-2 infections.

To develop an inhalable drug delivery system, we synthesized poly (lactic--glycolic acid) nanoparticles with Remdesivir (RDV NPs) as an antiviral agent against SARS-CoV-2 replication and formulated Remdesivir-loaded nanocomposites (RDV NCs) coating of RDV NPs with novel supramolecular cell-penetrating peptide nanofibers (NFs) to enhance cellular uptake and intracellular drug delivery. RDV NPs and RDV NCs were characterized using variou techniques, including Transmission Electron Microscopy (TEM), Dynamic Light Scattering (DLS), and fluorescent microscopy. The cytotoxicity of RDV NCs was assessed in Vero E6 cells and primary human lung epithelial cells, with no significant cytotoxicity observed up to 1000 μg mL and 48 h. RDV NCs were spherically shaped with a size range of 200-300 nm and a zeta potential of ∼+31 mV as well as indicating the presence of coated nanofibers. Reverse Transcription-quantitative Polymerase Chain Reaction (RT-qPCR), immunofluorescence and plaque assays of SARS-CoV-2 infected Vero E6 treated with RDV NCs showed significantly higher antiviral activities compared to those of free drug and uncoated RDV NPs. RDV NCs exhibited high antiviral activity against SARS-CoV-2, and the nanocomposite platform has the potential to be developed into an inhalable drug delivery system for other viral infections in the lungs.