Excellent Antimicrobial Activity of Fe₃O₄/SiO₂/Ag Nanocomposites

Abstract

In this study, a new antimicrobial agent was developed through a synthesis of Fe3O4/SiO2/Ag double nanocomposites using the sol–gel method. The prepared samples were characterized using XRD, SEM, FTIR, UV-Vis, VSM, and antibacterial test. The data analysis results for the Fe3O4/SiO2/Ag composites showed that Fe3O4, SiO2, and Ag constructed respective spinel cubic, orthorhombic, and amorphous structures in nanometric size. The saturation magnetization of Fe3O4/SiO2/Ag nanocomposites decreased due to the increase in the Ag content. Interestingly, the Fe3O4/SiO2/Ag nanocomposites presented excellent microbial activity. Ag deposition on the Fe3O4/SiO2 surface enhanced the antimicrobial activity of nanocomposites because Ag oxidized to Ag[Formula: see text] ion to produce a toxic effect in the cells of microorganisms. Furthermore, the Ag[Formula: see text] ion created the –S–Ag bond chain and deactivated the microorganism cells. Furthermore, surface plasmon resonance of Ag had an impact on the formation of photo-induced electrons, which produced superoxide radical anions, [Formula: see text] generating a collapsing force that causes the death of microorganisms.

Construction of Magnetic Nanochains to Achieve Magnetic Energy Coupling in Scaffold

“…The saturation magnetization of Fe 3 O 4 was 52.2 emu/g. The relatively low saturation magnetization of Fe 3 O 4 @SiO 2 was due to the introduction of non-magnetic SiO 2 shells decreased the weight ratio of Fe 3 O 4 in Fe 3 O 4 @SiO 2 [26]. This phenomenon was also discovered by M. Tarhini and A. Bitar et al [20,21].…”

Preparation of CoFe2O4/SiO2/Ag Magnetic Composite as Photocatalyst for Congo Red Dye and Antibacterial Potential

“…The value is lower than bulk CoFe2O4, which is ± 81 emu/g [26], but it is higher than CoFe2O4 synthesized using a combustion route, which is 39 emu/g [27]. The magnetic properties of a particle are influenced by particle size and homogeneity [18,23]. CoFe2O4/SiO2 composite sizes 42 and 8 nm had saturation magnetization values of 25 and 10 emu/g, respectively [28].…”

“…CoFe2O4/SiO2/Ag composite was synthesized using a modified procedure by Nikmah et al [23]. A total of 0.5 g of CoFe2O4/SiO2 was dispersed into a 20 mL solution containing 1.27 g PVP, 0.96 g NaOH, and 5.94 g glucose.…”

“…This research obtained the Minimum Inhibitory Concentration (MIC) value at the same concentration of 1.25%; however, the diameter of the inhibition zone of S. aureus is smaller than E. coli (Figure 11). The presence of SiO2 on the surface of Fe3O4 nanoparticles increases the antibacterial activity by acting as a molecular link between nanoparticles and microorganisms [23]. The interaction of SiO2 with cell membranes can change the structure and permeability of bacteria, causing the attraction of metal oxide nanoparticles into the microbial system and damaging the microbial cellular wall [46].…”

“…The antibacterial activity of CoFe2O4/SiO2 can be increased by adding Ag nanoparticles to kill bacteria and antibiotic resistance [21,22]. Moreover, Ag deposited on the CoFe2O4/SiO2 composite improved the antibacterial activity of the nanocomposite and is oxidized to Ag + ions, which leads to toxic effects on microorganism cells [23].…”