Hybrid Nanoparticles Based on Cobalt Ferrite and Gold: Preparation and Characterization

Optimization of cobalt ferrite magnetic nanoparticle as a theranostic agent: MRI and hyperthermia

OBJECTIVE

Magnetic nanoparticles (MNPs) are considered a theranostic agent in MR imaging, playing an effective role in inducing magnetic hyperthermia. Since, high-performance magnetic theranostic agents are characterized by superparamagnetic behavior and high anisotropy, in this study, cobalt ferrite MNPs were optimized and investigated as a theranostic agent.

METHODS

CoFe2O4@Au@dextran particles were synthesized and characterized by DLS, HRTEM, SEM, XRD, FTIR, and VSM methods. After cytotoxicity evaluation, MR imaging parameters (r1, r2 and r2 / r1) were calculated for these nanostructures. Afterward, magnetic hyperthermia at the frequency of 425 kHz was applied to calculate specific loss power (SLP).

RESULTS

Formation of CoFe2O4@Au@dextran was confirmed by UV-Visible spectrophotometry. On the basis of the relaxometric and hyperthermia induction findings of nanostructures in all stages of synthesis, the CoFe2O4@Au@dextran could produce the highest parameters of r2 and r2/r1 and SLP with values ​​of 389.7, 51.2 mM-1 s-1, and 2449 W/g, respectively.

CONCLUSION

The formation of multi-core MNPs by dextran coating is expected to improve the magnetic properties of the nanostructure, leading to optimization of theranostic parameters, so that CoFe2O4@Au@dextran NPs can create contrast-enhanced images more than three times the clinical use and require less contrast agent, reducing side effects. Accordingly, CoFe2O4@Au@dextran can be introduced as a suitable theranostic nanostructure with optimal efficiency.

Copper Ferrite Nanoparticles Synthesized Using Anion-Exchange Resin: Influence of Synthesis Parameters on the Cubic Phase Stability

Copper ferrite is of great interest to researchers as a material with unique magnetic, optical, catalytic, and structural properties. In particular, the magnetic properties of this material are structurally sensitive and can be tuned by changing the distribution of Cu and Fe cations in octahedral and tetrahedral positions by controlling the synthesis parameters. In this study, we propose a new, simple, and convenient method for the synthesis of copper ferrite nanoparticles using a strongly basic anion-exchange resin in the OH form. The effect and possible mechanism of polysaccharide addition on the elemental composition, yield, and particle size of CuFe₂O₄ are investigated and discussed. It is shown that anion-exchange resin precipitation leads to a mixture of unstable cubic (c-CuFe₂O₄) phases at standard temperature and stable tetragonal (t-CuFe₂O₄) phases. The effect of reaction conditions on the stability of c-CuFe₂O₄ is studied by temperature-dependent XRD measurements and discussed in terms of cation distribution, cooperative Jahn-Teller distortion, and Cu²⁺ and oxygen vacancies in the copper ferrite lattice. The observed differences in the values of the saturation magnetization and coercivity of the prepared samples are explained in terms of variations in the particle size and structural properties of copper ferrite.

Au-Loaded Superparamagnetic Mesoporous Bimetallic CoFeB Nanovehicles for Sensitive Autoantibody Detection

Construction of a well-defined mesoporous nanostructure is crucial for applying nonnoble metals in catalysis and biomedicine owing to their highly exposed active sites and accessible surfaces. However, it remains a great challenge to controllably synthesize superparamagnetic CoFe-based mesoporous nanospheres with tunable compositions and exposed large pores, which are sought for immobilization or adsorption of guest molecules for magnetic capture, isolation, preconcentration, and purification. Herein, a facile assembly strategy of a block copolymer was developed to fabricate a mesoporous CoFeB amorphous alloy with abundant metallic Co/Fe atoms, which served as an ideal scaffold for well-dispersed loading of Au nanoparticles (∼3.1 nm) via the galvanic replacement reaction. The prepared Au-CoFeB possessed high saturation magnetization as well as uniform and large open mesopores (∼12.5 nm), which provided ample accessibility to biomolecules, such as nucleic acids, enzymes, proteins, and antibodies. Through this distinctive combination of superparamagnetism (CoFeB) and biofavorability (Au), the resulting Au-CoFeB was employed as a dispersible nanovehicle for the direct capture and isolation of p53 autoantibody from serum samples. Highly sensitive detection of the autoantibody was achieved with a limit of detection of 0.006 U/mL, which was 50 times lower than that of the conventional p53-ELISA kit-based detection system. Our assay is capable of quantifying differential expression patterns for detecting p53 autoantibodies in ovarian cancer patients. This assay provides a rapid, inexpensive, and portable platform with the potential to detect a wide range of clinically relevant protein biomarkers.

The multimodal effect of Photothermal/Photodynamic/Chemo therapies mediated by Au-CoFe2O4 @Spiky nanostructure adjacent to mitoxantrone on breast cancer cells

BACKGROUND

Conventional cancer treatments are associated with a number of limitations, including non-selectivity, toxicity and multidrug resistance, so new nanotechnologies are being developed forcancer diagnosis and therapy. Phototherapy approach based on nanotechnology is a hopeful strategy to overcome these problems. Photothermal (PTT) and photodynamic therapies (PDT), in addition to having non-invasive properties, are known as promising methods for treatment of tumors. In this study, CoFe₂O₄ theranostic magnetic nanoparticles coated with spiky gold nanoparticles were designed and synthesized and its photothermal effects were evaluated in combination with the photodynamic and chemotherapeutic effects of mitoxantrone (MTX) under in vitro conditions.

METHODS AND MATERIALS

At first, CoFe₂O₄ @Spiky Au nanostructure was synthesized and after its characterization, cytotoxicity of MTX, CoFe₂O₄ @ Spiky Au (MGNS) and CoFe₂O₄ @ Au were determined on MDA-MB-231 cell line. Then, the concentrations required for inducing 50% cell death (IC₅₀) and appropriate concentration for this study was obtained. Cells were irradiated by an 808 nm laser and a non-synchronous light source at 670 nm at the separate groups. The viability of treated cells was determined via MTT test 48 h after treatment.

RESULTS

In the groups receiving energy density (5-40) J/cm², at the lower laser dose an increase in cell survival was observed (P < 0.05) and then cell survival was decreased (P < 0.05). In the groups receiving non-coherent light (2-18 J/cm²) from the beginning, a decreasing trend in cell survival is observed.

CONCLUSION

The overlap of the emission spectrum of the light source and the absorption spectrum of the nanostructure amplified the cell death. Similar to the Hormesis model reported for ionizing radiation effects, at low light doses with the bio-phasic response dose model, increased cell survival and proliferation can be expected.

Innovative Gold/Cobalt Ferrite Nanocomposite: Physicochemical and Cytotoxicity Properties

The combination of plasmonic material and magnetic metal oxide nanoparticles is widely used in multifunctional nanosystems. Here we propose a method for the fabrication of a gold/cobalt ferrite nanocomposite for biomedical applications. The composite includes gold cores of ~10 nm in diameter coated with arginine, which are surrounded by small cobalt ferrite nanoparticles with diameters of ~5 nm covered with dihydrocaffeic acid. The structure and elemental composition, morphology and dimensions, magnetic and optical properties, and biocompatibility of new nanocomposite were studied. The magnetic properties of the composite are mostly determined by the superparamagnetic state of cobalt ferrite nanoparticles, and optical properties are influenced by the localized plasmon resonance in gold nanoparticles. The cytotoxicity of gold/cobalt ferrite nanocomposite was tested using T-lymphoblastic leukemia and peripheral blood mononuclear cells. Studied composite has selective citotoxic effect on cancerous cells while it has no cytotoxic effect on healtly cells. The results suggest that this material can be explored in the future for combined photothermal treatment and magnetic theranostic.