Synthesis and Characterization of Core–Shell Magnetic Nanoparticles NiFe2O4@Au

Advances in surface design and biomedical applications of magnetic nanoparticles

Despite significant efforts by scientists in the development of advanced nanotechnology materials for smart diagnosis devices and drug delivery systems, the success of clinical trials remains largely elusive. In order to address this biomedical challenge, magnetic nanoparticles (MNPs) have gained attention as a promising candidate due to their theranostic properties, which allow the simultaneous treatment and diagnosis of a disease. Moreover, MNPs have advantageous characteristics such as a larger surface area, high surface-to-volume ratio, enhanced mobility, mass transference and, more notably, easy manipulation under external magnetic fields. Besides, certain magnetic particle types based on the magnetite (Fe3O4) phase have already been FDA-approved, demonstrating biocompatible and low toxicity. Typically, surface modification and/or functional group conjugation are required to prevent oxidation and particle aggregation. A wide range of inorganic and organic molecules have been utilized to coat the surface of MNPs, including surfactants, antibodies, synthetic and natural polymers, silica, metals, and various other substances. Furthermore, various strategies have been developed for the synthesis and surface functionalization of MNPs to enhance their colloidal stability, biocompatibility, good response to an external magnetic field, etc. Both uncoated MNPs and those coated with inorganic and organic compounds exhibit versatility, making them suitable for a range of applications such as drug delivery systems (DDS), magnetic hyperthermia, fluorescent biological labels, biodetection and magnetic resonance imaging (MRI). Thus, this review provides an update of recently published MNPs works, providing a current discussion regarding their strategies of synthesis and surface modifications, biomedical applications, and perspectives.

Nickel-doped magnetic carbon aerogel derived from xanthan gum: a competent catalyst for the degradation of single and binary dye-based water pollutants

Toxic organic dyes (colorants) are one of the main causes of water pollution that releases destructive effluents in the environment. To overcome this issue, a fundamental need to produce a novel, efficient catalyst for the degradation and mineralization of dye mixtures has arisen. The objective of this research is to develop an eminent Ni-doped magnetic carbon aerogel (Ni-MCA) catalyst using graft co-polymerization method having xanthan gum as backbone doped with Ni-magnetic nanoparticles (Ni-MNPs), that do not show agglomeration and easy to separate. The examination revealed that Ni-MCA provided exceptional magnetic characteristics (Ms = 52.75 emu/g) and potent catalytic activity for the degradation of mono- as well as binary-dye solutions of Congo red (CR) and methyl green (MG) dyes. The formation was verified by various characterization techniques such as FTIR, VSM, XRD, XPS, SEM, TEM, and EDX mapping. Interestingly, Ni-MCA shows faster result on anionic dye CR up to 97% with degradation rate of 5.647 × 10-1 min-1, and MG dye shows degradation of 95.7% with the degradation rate of 2.169 × 10-1 min-1, while dye mixture is showing 90% degradation with rate of 2.159 × 10-1 min-1.

Electrospun Magnetic Nanofiber Mats for Magnetic Hyperthermia in Cancer Treatment Applications-Technology, Mechanism, and Materials

The number of cancer patients is rapidly increasing worldwide. Among the leading causes of human death, cancer can be regarded as one of the major threats to humans. Although many new cancer treatment procedures such as chemotherapy, radiotherapy, and surgical methods are nowadays being developed and used for testing purposes, results show limited efficiency and high toxicity, even if they have the potential to damage cancer cells in the process. In contrast, magnetic hyperthermia is a field that originated from the use of magnetic nanomaterials, which, due to their magnetic properties and other characteristics, are used in many clinical trials as one of the solutions for cancer treatment. Magnetic nanomaterials can increase the temperature of nanoparticles located in tumor tissue by applying an alternating magnetic field. A very simple, inexpensive, and environmentally friendly method is the fabrication of various types of functional nanostructures by adding magnetic additives to the spinning solution in the electrospinning process, which can overcome the limitations of this challenging treatment process. Here, we review recently developed electrospun magnetic nanofiber mats and magnetic nanomaterials that support magnetic hyperthermia therapy, targeted drug delivery, diagnostic and therapeutic tools, and techniques for cancer treatment.

Synthesis and Characterization of Tetracycline Loaded Methionine-Coated NiFe2O4 Nanoparticles for Anticancer and Antibacterial Applications

In the present study, nickel ferrite (NiFe₂O₄)-based smart magnetic nanoparticles were fabricated and coated with methionine. Physiochemical characterization of the obtained Met-NiFe₂O₄ nanoparticles revealed the presence of methionine coating over the nanoparticle surface. Drug release study indicated that Tet-Met-NiFe₂O₄ nanoparticles possess pH-responsive controlled drug release behavior for tetracycline (Tet). The drug loading content for Tet was found to be 0.27 mg/L of nanoparticles. In vitro cytotoxicity test showed that the Met-NiFe₂O₄ nanoparticles is biocompatible. Moreover, this magnetic nanostructured material shown strong anticancer property as these nanomaterials significantly reduced the viability of A375 cells when compared to free Tet solution. In addition, Tet-Met-NiFe₂O₄ nanoparticles also showed strong antibacterial activity against different bacterial pathogens.

Laser Ablation of NiFe2O4 and CoFe2O4 Nanoparticles

Pulsed laser ablation in liquids was utilized to prepare NiFe2O4 (NFO) and CoFe2O4 (CFO) nanoparticles from ceramic targets. The morphology, crystallinity, composition, and particle size distribution of the colloids were investigated. We were able to identify decomposition products formed during the laser ablation process in water. Attempts to fractionate the nanoparticles using the high-gradient magnetic separation method were performed. The nanoparticles with crystallite sizes in the range of 5-100 nm possess superparamagnetic behavior and approximately 20 Am2/kg magnetization at room temperature. Their ability to absorb light in the visible range makes them potential candidates for catalysis applications in chemical reactions and in biomedicine.

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.

Polyethylenimine-Modified Magnetic Chitosan for the Uptake of Arsenic from Water

The removal of heavy metals from water has become a global environmental problem. Various materials have been applied as adsorbent to remove metals from water. In this field, nanomaterials have been gaining increasing interest due to their exceptional properties. In this work, we discuss the synthesis of a core-shell structure nanocomposite by the modification of magnetic chitosan (CS) (Fe3O4/CS) with polyethylenimine (PEI) to produce Fe3O4/CS/PEI composite for the adsorption of arsenic ions (As(V) and As(III)) from aqueous solution. The synthesized materials were characterized using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), transmission electron microscope (TEM), and vibrating sample magnetometer (VSM). The results indicated the successful combination of three components of the nanocomposite. The adsorption conditions were optimized by studying the effect of different parameters included pH, contact time, initial concentration, and adsorbent dosage. The optimum adsorption pH was found to be 6.7 while the optimum adsorbent dosage was found to be 2.0 and 1.5 g/L for As(III) and As(V), respectively. The removal efficiency for the uptake of As(III) and As(V) ions over Fe3O4/CS/PEI nanocomposite at optimum conditions was found to be 99.5 and 99.7%, respectively. The experimental results were fitted using Freundlich’s and Langmuir’s isotherms. The data were more fitted to Langmuir isotherm providing a suggestion of monolayer adsorption with maximum adsorption capacity equal to 77.61 and 86.50 mg/g for the removal of As(III) and As(V), respectively. Moreover, linear regression coefficient (R2) indicated that the adsorption of arsenic ions over the synthesized magnetic nanocomposite obeyed pseudo 2nd order suggesting the chemisorption process. The reusability of the nanosorbent for arsenic uptake using sodium hydroxide as eluent was also assessed up to five cycles. Interestingly, Fe3O4/CS/PEI nanocomposite can be considered as a promising adsorbent for As ions’ removal from water and should be tested for the removal of other pollutants.

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

During the past few decades, hybrid nanoparticles (HNPs) based on a magnetic material and gold have attracted interest for applications in catalysis, diagnostics and nanomedicine. In this paper, magnetic CoFe2O4/Au HNPs with an average particle size of 20 nm, decorated with 2 nm gold clusters, were prepared using methionine as a reducer and an anchor between CoFe2O4 and gold. The methionine was used to grow the Au clusters to a solid gold shell (up to 10 gold deposition cycles). The obtained nanoparticles (NPs) were studied by X-Ray diffraction (XRD), transmission electron microscopy (TEM), Fourier-transform infrared (FT-IR) spectroscopy, X-Ray photoelectron spectroscopy (XPS) and UV-vis spectroscopy techniques. The TEM images of the obtained HNPs showed that the surface of cobalt ferrite was covered with gold nanoclusters, the size of which slightly increased with an increase in the number of gold deposition cycles (from 2.12 ± 0.15 nm after 1 cycle to 2.46 ± 0.13 nm after 10 cycles). The density of the Au clusters on the cobalt ferrite surface insignificantly decreased during repeated stages of gold deposition: 21.4 ± 2.7 Au NPs/CoFe2O4 NP after 1 cycle, 19.0 ± 1.2 after 6 cycles and 18.0 ± 1.4 after 10 cycles. The magnetic measurements showed that the obtained HNPs possessed typical ferrimagnetic behavior, which corresponds to that of CoFe2O4 nanoparticles. The toxicity evaluation of the synthesized HNPs on Chlorella vulgaris indicated that they can be applied to biomedical applications such as magnetic hyperthermia, photothermal therapy, drug delivery, bioimaging and biosensing.