Synthesis and Characterization of Citric Acid-Modified Iron Oxide Nanoparticles Prepared with Electrohydraulic Discharge Treatment

Abstract

Chemical co-precipitation from ferrous and ferric salts at a 1:1.9 stoichiometric ratio in NH4OH base with ultrasonication (sonolysis) in a low vacuum environment has been used for obtaining colloidal suspensions of Fe3O4 nanoparticles coated with citric acid. Before coating, the nanoparticles were processed by electrohydraulic discharges with a high discharge current (several tens of amperes) in a water medium using a pulsed direct current. Magnetite nanoparticles were obtained with an average crystallite diameter D = 25–28 nm as obtained by XRD and particle sizes of 25 nm as measured by small-angle X-ray scattering. Magnetometry showed that all samples were superparamagnetic. The saturation magnetization for the citric acid covered samples after electrohydraulic processing showed higher value (58 emu/g) than for the directly coated samples (50 emu/g). Ultraviolet-visible spectroscopy and Fourier transform infrared spectroscopy showed the presence and binding of citric acid to the magnetite surface by chemisorption of carboxylate ions. Hydrodynamic sizes obtained from DLS and zeta potentials were 93 and 115 nm, −26 and −32 mV for the citric acid covered nanoparticles and 226 nm and 21 mV for the bare nanoparticles, respectively. The hydraulic discharge treatment resulted in a higher citric acid coverage and better particle dispersion. The developed method can be used in nanoparticle synthesis for biomedical applications.

Therapeutic Potential of Methotrexate-Loaded Superparamagnetic Iron Oxide Nanoparticles Coated with Poly(lactic-co-glycolic acid) and Polyethylene Glycol against Breast Cancer: Development, Characterization, and Comprehensive In Vitro Investigation

“…Superparamagnetic magnetite (Fe 3 O 4 ) nanoparticles were prepared using an improved chemical coprecipitation. 14 Concisely, 3.1736 g of FeCl 2 ·4H2O (0.016 mol) and 7.5684 g of FeCl 3 ·6H 2 O (0.028 mol) were dissolved in 320 mL of deionized water, such that Fe 2+ /Fe 3+ = 1/1.75. Subsequently, ammonium hydroxide was added to the mixture in the presence of nitrogen gas with vigorous stirring ( Figure 1 A).…”

Synthesis, Characterization, and In Vitro Cytotoxicity Evaluation of Doxorubicin-Loaded Magnetite Nanoparticles on Triple-Negative Breast Cancer Cell Lines

“…Among many small organic molecules, citric acid (CA, C 6 H 8 O 7 ), with three carboxyls (COOH) and one hydroxyl (OH) group, is a highly water-soluble compound with strong polarity, so it can be used as a surfactant to obtain stable magnetic water-based nanoparticles [ 48 , 49 ]. It can be chemisorbed on the surface of the magnetite nanoparticles via one of the two carboxylate groups.…”

Rheology of Aqueous Ferrofluids: Transition from a Gel-Like Character to a Liquid Character in High Magnetic Fields

“…Therefore, the magnetic nanoparticles are coated with different molecules that provide additional electrostatic and/or steric repulsion. Shorter molecules, i.e., citric acid [30,31], provide additional electrostatic charge, which prevents agglomeration of nanoparticles. The longer molecules such as sodium oleate [32], oleic acid [28,33], and sodium dodecyl benzene sulfonate [11] will provide steric repulsion and, in the case of the bilayer, also electrostatic charge.…”