Amphotericin B (AMB) has long been considered the most effective drug in the treatment of
serious invasive fungal infections. There are, however, major limitations to its use, due to several adverse effects,
including acute infusional reactions and, most relevant, a dose-dependent nephrotoxicity. At least some of these
effects are attributed to the aggregation of AMB as a result of its poor water solubility. To overcome this problem,
reformulated versions of the drug have been developed, including a micellar dispersion of AMB with sodium
deoxycholate (AMBD), its encapsulation into liposomes, or its incorporation into lipidic complexes. The
development of nanobiotechnologies provides novel potential drug delivery systems that make use of
nanomaterials such as functionalized carbon nanotubes (f-CNTs), which are emerging as an innovative and
efficient tool for the transport and cellular translocation of therapeutic molecules. In this study, we prepared
two conjugates between f-CNTs and AMB. The antifungal activity of these conjugates was tested against a
collection of reference and clinical fungal strains, in comparison to that of AMB alone or AMBD. Measured minimum
inhibition concentration (MIC) values for f-CNTAMB conjugates were either comparable to or better than those
displayed by AMB and AMBD. Furthermore, AMBD-resistant Candida strains were found to be susceptible to f-
CNTAMB 1. Additional studies, aimed at understanding the mechanism of action of the conjugates, suggest a
nonlytic mechanism, since the compounds show a major permeabilizing effect on the tested fungal strains only
after extended incubation. Interestingly, the f-CNTAMB 1 does not show any significant toxic effect on Jurkat
cells at antifungal concentrations.
