Carbon nanohorns with surface functionalized by plasma treatment and their applications in drug delivery systems

Abstract

Carbon nanohorns (CNHs) were produced and employed for the controlled release of polyvinylpyrrolidone-iodine (PVPI). CNHs with unique surface properties were produced via the gas-injected arc-in-water method incorporated with surface modification by oxygen plasma treatment. As confirmed by Raman analysis, prolongation of irradiation time (0.5–60 min) and an increase in pressure (1–20 mbar) could lead to a higher amount of graphitic carbon in CNHs after oxygen plasma treatment. In addition, the formation of carboxyl groups on the surface of modified CNHs, which was confirmed by FTIR spectra and the titration method, could enhance the stability of CNH dispersion and the slow-release efficacy of PVPI. The rate constant of pure PVPI release was 16.3 g/mg min, whereas the rate constants of PVPI impregnated onto pristine CNHs and modified CNHs were 0.88 and 0.19 g/mg min, respectively. These results indicated a significant improvement in the slow-release performance of CNHs after plasma modification. Accordingly, the facile synthesis and modification of CNHs by oxygen plasma treatment would be a promising method to produce CNHs for drug delivery applications.

Keywords

• Carbon nanohorn
• Poly-vinylpyrrolidone-iodine
• Controlled release
• Arc-in-water
• Oxygen plasma treatment