Synthesis, Characterization, and Applications of Dendrimer-Encapsulated Zero-Valent Ni Nanoparticles as Antimicrobial Agents

Dendrimers have emerged as one of the most promising, cost-effective synthesizing methodologies in which highly monodispersed metallic nanoparticles can be produced with varied chemical functionalities. In this report, we have investigated the synthesis and application of as-synthesized dendrimer-encapsulated zero-valent nickel “Ni(0)” nanoparticles (NPs), using a fourth generation (G4) NH2-terminated poly(amido)amine (PAMAM) dendrimer as the host template, as potential antimicrobial agents. Apparently, based on ultraviolet visible spectroscopy (UV-vis) and transmission electron microscopy (TEM) analyses, Ni(0) NPs with an average measured size less than 10 nm in diameter were formed within the interior void cavity of the dendrimer structure. X-ray diffraction (XRD) analysis indicates that the NPs exhibited a single-phased, face-centered-cubic (fcc) crystallographic structure. Furthermore, to evaluate the antimicrobial activity of the dendrimer-encapsulated Ni(0) NPs, disk diffusion assay and minimum inhibitory concentration (MIC) examinations, both antimicrobial tests, were conducted. Subsequently, UV-vis analyses, after exposure of the dendrimer-encapsulated Ni(0) NPs to both Gram-negative and Gram-positive bacteria, revealed that the dendrimer-encapsulated particles prevented the growth of bacteria during the culturing stage.