Antimicrobial alumina nanobiostructures of disulfide- and triazole-linked peptides: Synthesis, characterization, membrane interactions and biological activity

Due to the its physical-chemical properties, alumina nanoparticles have potential applications in several areas, such as nanobiomaterials for medicinal or orthodontic implants, although the introduction of these devices poses a serious risk of microbial infection. One convenient strategy to circumvent this problem is to associate the nanomaterials to antimicrobial peptides with broad-spectrum of activities. In this study we present two novel synthesis approaches to obtain fibrous type alumina nanoparticles covalentiy bound to antimicrobial peptides. In the first strategy, thiol functionalized alumina nanoparticles were linked via disulfide bond formation to a cysteine residue of an analog of the peptide BP100 containing a four amino acid spacer (Cys-Ala-Ala-Ala). In the second strategy, alumina nanoparticles were functionalized with azide groups and then bound to alkyne-decorated analogs of the peptides BP100 and DD K through a triazole linkage obtained via a copper(I)-catalyzed cycloaddition reaction. The complete physical-chemical characterization of the intermediates and final materials is presented along with in vitro biological assays and membrane interaction studies, which confirmed the activity of the obtained nanobiostructures against both bacteria and fungi. To our knowledge, this is the first report of aluminum nanoparticles covalentiy bound to triazole-peptides and to a disulfide bound antimicrobial peptide with high potential for biotechnological applications.