Characterization of ester- or thioamide-functionalized single-walled carbon nanotube-azithromycin conjugates

Functionalization of single-walled carbon nanotubes (SWCNTs) with nitrile groups, followed by further reactions allowed direct attachment of azithromycin and its N-demethyl derivative to the side-walls of SWCNTs for the first time. With these approaches, the cleavable ester or thioamide bonds are formed to connect azithromycin to SWCNTs resulting in azithromycin-SWCNT conjugates. These cleavable bonds are able to control molecular release from nanotube surfaces which are generally applicable to a variety of hybrid materials based on SWCNTs. A non-covalent azithromycin-SWCNT has also been compared with azithromycin-SWCNTs conjugates. Thermogravimetric analysis (TGA), Fourier-transformed infrared (FT-IR), UV–vis, and Raman spectroscopies give hints on the characterization of azithromycin-SWCNT. Both drug release and antimicrobial activity of azithromycin-SWCNT conjugates were also tested.