Carboxylated SiO2-coated α-Fe nanoparticles: towards a versatile platform for biomedical applications

Abstract

Carboxylated SiO2-coated α-Fe nanoparticles have been successfully prepared via CaH2-mediated reduction of SiO2-coated Fe3O4 nanoparticles followed by surface carboxylation. These α-Fe-based nanoparticles, which are characterized by ease of coating with additional functional groups, a large magnetization of 154 emu per g-Fe, enhanced corrosion resistivity, excellent aqueous dispersibility, and low cytotoxicity, have potential to be a versatile platform in biomedical applications.

Preparation of SiO2-Protecting Metallic Fe Nanoparticle/SiO2 Composite Spheres for Biomedical Application

“…Therefore, it is difficult to observe the crystallization of the Fe NPs on SiO 2 . Martinez et al prepared amorphous SiO 2 by a sol-gel procedure and observed in the XRD pattern a broad peak around 2θ = 21.8° corresponding to amorphous SiO 2 [8]. Therefore, the peak at 2θ = 21° may result from the amorphous SiO 2 layer.…”

“…From the viewpoint of practical applications, any method to fabricate Fe NPs must take into account the susceptibility of Fe NPs to oxidation and aggregation owing to the magnetic interaction between the particles. Controlling the oxidation of Fe NPs is particularly important, as oxidation leads to a degradation in their magnetic properties [3,8]. Since Fe NPs are oxidized rapidly in water and air, they exhibit a loss or decrease in magnetism and dispersibility in a biological environment.…”

“…To prevent the oxidation of Fe NPs, the core-shell structures that are stable, biocompatible and hydrophilic were demonstrated using surface modifications with organic polymers of poly(acrylic acid) [9], poly(ethylene glycol) [10], dendrimers [11], chitosan [12,13] and silica (SiO 2 ) layers [7,8]. The SiO 2 shells provide an electrically-insulting layer that decreases energy loss and additionally prevents the possibility of a decrease in permeability due to Fe oxidation [7].…”

Factors affecting the physicochemical properties of the modified core/shell NH2–SiO2@NZVI nanoparticles

“…Wang et al [18] developed a novel magnetic amino-functionalized Fe 3 O 4 @SiO 2 nanomaterial with a core/shell structure to remove heavy metal ions from aqueous media and found that with amino groups grafted on the silica surface, the nanomaterial showed superior reactivity and high adsorption affinity. Kaori et al [12] have successfully prepared monodispersed Fe@SiO 2 @COOH NPs via CaH 2 -mediated reduction of SiO 2 -coated Fe 3 O 4 nanoparticles followed by modification with COOH-silane. And these particles showed a very high saturation magnetization, enhanced controlled morphology, corrosion resistivity, and low cytotoxicity.…”

“…The poor hydrophobicity of iron surface is another reason for the lower efficiency of NZVI on removing organic contaminants [1]. So, development of methodologies for the preparation of surface-protected corrosion-resistive NZVI particles has been a key demand [12].…”