Synthesis, physical characterization, and antifungal and antibacterial activities of oleic acid capped nanomagnetite and cobalt-doped nanomagnetite

Abstract

Nanoparticles, 10–14 nm, consisting of either Fe3O4 or Co0.2Fe2.8O4 stabilized with oleic acid, were prepared using solution combustion. Their structural and magnetic properties were examined using X-ray diffractometry, scanning electron microscopy, vibrating sample magnetometry, and Fourier-transform infrared spectroscopy. The properties of both sets of materials are similar, except that the cobalt-doped particles are considerably less magnetic. The in vitro inhibitory activities of the nanoparticles were assessed against pathogenic bacteria Shigella dysenteriae, Klebsiella pneumoniae, Acinetobacter baumannii, Streptococcus pyogenes, and pathogenic fungi and molds Candida albicans, Fusarium oxysporum, and Aspergillus fumigatus. The magnetite nanoparticles were moderately effective against all tested pathogens, but the activity of the cobalt-doped nanoparticles was significantly lower, possibly due to an interruption of the Fenton reaction at the bacterial membrane. This work suggests that potentially doping magnetite with stronger metal oxidants may instead enhance their antimicrobial effects.

The Promise of Metal-Doped Iron Oxide Nanoparticles as Antimicrobial Agent

“…aureus). ,,, Doping activity of ZDI at the lowest concentration was comparatively higher than any other doped-IONPs . Apart from ZOI, minimum inhibitory concentration (MIC) was performed to determine the lowest concentration which can inhibit the growth. − ,,, Studies of NDI and ZDI have shown higher MIC with the lowest amount on E. coli, B. subtilis , S. typhi , K. pneumonia , while MDI has shown no significant inhibition of E.…”

“…Doped-IONPs are composed of modified iron oxides by introducing foreign metals or elements into their structure. ,,,− Introduction of foreign metals, also known as dopants, into an empty crystal lattice alters the physicochemical, biological, electrical, as well as optical properties of the nanoparticles . Doped-IONPs can be synthesized by coprecipitation (CP), green combustion (GC), sol–gel process (SGP), chemical polymerization approach (CPA), microwave-assisted process (MAP), hydrothermal approach (HDA). ,,,,,− Multiple types of dopants, e.g.…”

“…Doped-IONPs are composed of modified iron oxides by introducing foreign metals or elements into their structure. ,,,− Introduction of foreign metals, also known as dopants, into an empty crystal lattice alters the physicochemical, biological, electrical, as well as optical properties of the nanoparticles . Doped-IONPs can be synthesized by coprecipitation (CP), green combustion (GC), sol–gel process (SGP), chemical polymerization approach (CPA), microwave-assisted process (MAP), hydrothermal approach (HDA). ,,,,,− Multiple types of dopants, e.g. , cobalt, nickel, copper, zinc, and rare-earth elements are broadly applied for doping purposes. ,,,, At present, doped-IONPs have found widespread applications in drug delivery, antimicrobial and anticancer activities, MRI imaging agent. − Moreover, when doped-IONPs are employed as antimicrobial agents, transition metals are mainly utilized due to their antimicrobial characteristics in their bulk form …”

“…One of the notable modifications is the enhancement of antimicrobial activity through different doping methods . Doped-IONPs sized around 20–200 nm have shown significant antimicrobial activity on different bacteria, where size less than 20 nm. ,, While doped-IONPs larger than 200 nm demonstrated comparatively poor antimicrobial activity. − ,,, Additionally, IONPs doped with transition metals shown significant antimicrobial activity based on the synthesis process, size, concentrations, and application. ,, Doped-IONPs were synthesized by using CP, CPA, MAP, GC, SGP, HDA, and solvothermal approach. However, the CP method was the most approached one due to its less complexity. ,,,, Moreover, the core advantage of the CP method over other synthesis methods is generating a large scale of nanoparticles.…”

“…Similarly, the insertion of foreign metal particles into IONPs alter their physicochemical, as well as biological, electrical, and optical, properties and improve performance compared to bare IONPs . IONPs are doped with several metals, and their oxides, such as Ni, , Cu, , Co, Zn, , Se, Mo, Au, , ZnO, , CuO, exhibit antimicrobial activity toward pathogenic bacteria.…”