Nitric Oxide Gas in Carbon Nanohorn/Fluorinated Dendrimer/Fluorinated Poly(ethylene glycol)-Based Hierarchical Nanocomposites as Therapeutic Nanocarriers.

Abstract

Nitric oxide (NO) gas nanocarrier materials were prepared via a hierarchical assembly of poly(amido amine) dendrimers with fluorocarbon binding sites (DEN-F) and fluorinated poly(ethylene glycol) (F-PEG) on nitrogen-doped carbon nanohorns (NCNHs). The loading abilities of NO gas in these nanocarrier materials increased with the nitrogen doping of CNH and hierarchies formed by DEN-F and F-PEG. Especially, the ability of CNH-based nanocomposite materials was better than that of graphene-based materials. The loading of NO gas arose an infrared absorption band at 1387 cm-1 and increased the intensity ratio of D and G bands in Raman spectra, although these phenomena diminished after the degas treatment. The antimicrobial effects on bacteria (Escherichia coli and Staphylococcus aureus) increased depending on the loading amount of NO gas. It was confirmed from these results that NO gas weakly interacts with nitrogen-doped CNH and is trapped in the void volumes of DEN-F and F-PEG hierarchies. Thus, the concentric hierarchy is preferable for slow release of NO gas due to the void volumes in DEN-F, F-PEG, and CNH hierarchical organization. This sustained release of NO gas is advantageous with regards to the potential biomedical gas therapy against bacteria and other parasites.