Nanostructured Hematite Decorated with Gold Nanoparticles for Functionalization and Biocompatibility

Abstract

Iron oxides have attracted the attention of researchers due to their abundance, low cost, low toxicity, and versatility of applications. According to the composition and crystalline structure, iron oxides may have characteristics of semiconductors and magnetic materials, such as hematite (α‐Fe2O3) and magnetite (Fe3O4), respectively. The property of biocompatibility of hematite is essential to be applied in the construction of micro‐/nanorobots (MNRs). Herein, the decoration of hierarchically structured core/shell Fe3O4/Fe2O3 microtubes and foils with gold nanoparticles (AuNPs) for functionalization and enhancement of biocompatibility that favor the use in MNR fabrication is presented. In this case, the synthesis of AuNPs takes advantage of the capacity of hematite to reduce Au3+ photochemically under excitation by a sunlight simulator. The yield of AuNPs covering the microtube surface is dependent on the gold salt concentration used for the synthesis. The AuNP‐decorated hematite surfaces of the microtube and foil are functionalized with thiol poly(ethylene glycol) fluorescein, exhibiting increase in conductivity favored by irradiation with visible light. AuNPs also favor cell adherence and proliferation with the maintenance of mitochondrial transmembrane potential. Therefore, the hematite surface of the microtubes decorated with AuNPs is a promising material for the application in micro‐/nanorobots and bioelectronics.

Preparation and characterization of α-Fe2O3/Fe3O4 heteroplasmon nanoparticles via the hydrolysis-combustion-calcination process of iron nitrate

“…Combining the merit and demerit of the α-Fe , but its experimental period was length. Menezes et al [22] prepared Fe 2 O 3 /Fe 3 O 4 microtubes via the thermal oxidation process of a high-purity metallic iron microwire. However, the temperature of the experimental process was too high to apply widely, and Fe 2 O 3 /Fe 3 O 4 microtubes had a larger diameter and uncontrollable magnetism.…”

Designing a Multifunctional Magnetic Microtube with Enhanced Conductivity through Local Heterojunction Decoration of CsPbBr3 Nanocrystals

“…Recently, efforts have been dedicated to combine different semiconductors into a single heterostructured system in order to achieve new improved properties. , Among the possibilities of using heterostructure hollow materials based on the Fe 2 O 3 /Fe 3 O 4 microarchitecture, recent reports have shown that the microtube modification with plasmonic nanoparticles increases biocompatibility, electronic transport, and light-assisted charge transfer, which opens up opportunities for applications in micro and bioelectronics. , …”

Iron Oxide Nanoparticles in Cancer Treatment: Cell Responses and the Potency to Improve Radiosensitivity

“…Depending on the spatial structure of molecules and the oxidation state of iron, there are three most common forms of IONPs structurally corresponding to iron oxide minerals: magnetite (FeO*Fe 3 O 4 ), maghemite (γ-Fe 2 O 3 ), and hematite (α-Fe 2 O 3 ) [5]. While α-Fe 2 O 3 nanostructures are applied in designing micro/nanorobots [6,7], FeO*Fe 3 O 4 and γ-Fe 2 O 3 are widely used in diagnostics and therapy. In practice, these are employed in the treatment of iron deficiency anemia [8], as a contrast agent for magnetic resonance imaging (MRI) [9,10], and in the development of various antitumor strategies: magnetic hyperthermia [11,12], targeted delivery, and tumor sensitization [13][14][15][16].…”