Hierarchical Structure and Magnetic Behavior of Zn-Doped Magnetite Aqueous Ferrofluids Prepared from Natural Sand for Antibacterial Agents

Abstract

This study performs natural sand-based synthesis using the sonochemical route for preparing Zn-doped magnetite nanoparticles. The nanoparticles were dispersed in water as a carrier liquid to form Zn-doped magnetite aqueous ferrofluids. Structural data analysis indicated that the Zn-doped magnetite nanoparticles formed a nanosized spinel structure. With an increase in the Zn content, the lattice parameters of the Zn-doped magnetite nanoparticles tended to increase because Zn 2+ has a larger ionic radius than those of Fe 3+ and Fe 2+ . The existence of Zn-O and Fe-O functional groups in tetrahedral and octahedral sites were observed in the wavenumber range of 400-700 cm -1 . The primary particles of the Zn-doped magnetite ferrofluids tended to construct chain-like structures with fractal dimensions of 1.2-1.9. The gas-like compression (GMC) plays as a better model than the Langevin theory to fit the saturation magnetization of the ferrofluids. The ferrofluids exhibited a superparamagnetic character, with their magnetization was contributed by aggregation. The Zn-doped magnetite ferrofluids exhibited excellent antibacterial activity against gram-positive and negative bacteria. It is suggested that the presence of the negatively charged surface and the nanoparticle size may contribute to the high antibacterial activity of Zn-doped magnetite ferrofluids and making them potentially suitable for advanced biomedical.

Zinc/Cerium-Substituted Magnetite Nanoparticles for Biomedical Applications

“…In terms of antimicrobial activity, the available literature demonstrates the potential of both zinc/cerium-substituted magnetite nanoparticles and zinc/cerium oxide nanoparticles against a wide variety of microbial species, e.g., B. cereus [ 19 ], B. subtilis [ 24 , 60 ], S. aureus [ 20 , 32 , 60 , 61 , 62 ], S. enterica [ 63 ], E. coli [ 19 , 20 , 24 , 60 , 61 , 62 , 63 , 64 ], P. aeruginosa [ 60 , 65 ], C. jejuni [ 63 ], and C. albicans [ 19 ]. While the mechanistic pathway behind the activity of zinc/cerium-substituted magnetite nanoparticles has not been precisely determined, it could be assumed that it is based on the targeting of the microbial cell wall, followed by the release of the zinc and cerium ions within the microbial environment and the consequent generation of intracellular reactive oxygen species [ 31 , 60 ].…”

“…While zinc ion concentrations are physiologically regulated through homeostasis to prevent excess cell uptake and toxicity, above optimum levels allow cell entry and cytotoxicity towards prokaryotes [ 20 ]. In this context, zinc can be used as an efficient inhibitor of bacterial and fungal strain growth [ 20 , 24 , 25 ]. Furthermore, numerous studies have reported the tumor suppressor effects of zinc, which generally involve the alteration of bioenergetic and metabolic mechanisms, inhibition of cell cycle activity and, consequently, of malignant advancement to metastasis and promotion of apoptosis [ 26 , 27 ].…”

“…In this manner, incorporating zinc and/or cerium ions within the structure of magnetite nanoparticles could enhance its biomedical properties in terms of antioxidant, anticancer, and antimicrobial potential [ 24 , 32 ]. Nonetheless, zinc/cerium-substituted magnetite nanoparticle-based studies are considerably limited, especially within the biomedical field.…”