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. 1. Introduction Interest in nanoparticles synthesis has intensified within the scientific community due to their large amount of surface-area-to-volume ratio, which can be modified for use in a wide range of technological and chemical systems. As of date, nanosized inorganic particles with simple or complex structures are currently being used in electronics [1], optical devices [2, 3], sensor devices [4, 5], surface enhanced Raman scattering (SERS) [6, 7], catalysis [8–10], biomedicine [11], wound healing [12], antimicrobial properties [13, 14], gene expression [15], and magnetic resonance imaging [16]. However, due to the limitation of current synthesizing methodologies to produce nanoparticles with precise physical and chemical details, concerns have increased over nanoparticle usage in the healthcare industry. Furthermore, with increasing microbial organisms’ resistant to various antibiotics and uncertainties in healthcare costs, the emergence of more cost effective new methodologies to produce nanosized particles with specific physical and chemical functionalities and with limited or no resistance has piqued the interest of scientists around the globe [11–15]. That is, the development of more cost efficient synthetic
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