BackgroundSuperparamagnetic iron oxide nanoparticles (SPIONs) are the most commonly used negative MRI contrast agent which affect the transverse (T2) relaxation time. The aim of the present study was to investigate the impact of various polymeric coatings on the performance of magnetite nanoparticles as MRI contrast agents.MethodsFerrofluids based on magnetite (Fe3O4) nanoparticles (SPIONs) were synthesized via chemical co-precipitation method and coated with different biocompatible polymer coatings including mPEG-PCL, chitosan and dextran.ResultsThe bonding status of different polymers on the surface of the magnetite nanoparticles was confirmed by the Fourier transform infrared spectroscopy (FT-IR) and thermogravimetric analysis (TGA). The vibrating sample magnetometer (VSM) analysis confirmed the superparamagnetic behavior of all synthesized nanoparticles. The field–emission scanning electron microscopy (FE-SEM) indicated the formation of quasi-spherical nanostructures with the final average particle size of 12–55 nm depending on the type of polymer coating, and X-ray diffraction (XRD) determined inverse spinel structure of magnetite nanoparticles. The ferrofluids demonstrated sufficient colloidal stability in deionized water with the zeta potentials of −24.2, −16.9, +31.6 and −21 mV for the naked SPIONs, and for dextran, chitosan and mPEG-PCL coated SPIONs, respectively. Finally, the magnetic relaxivities of water based ferrofluids were measured on a 1.5T clinical MRI instrument. The r2/r1 value was calculated to be 17.21, 19.42 and 20.71 for the dextran, chitosan and mPEG-PCL coated SPIONs, respectively.ConclusionsThe findings demonstrated that the value of r2/r1 ratio of mPEG-PCL modified SPIONs is higher than that of some commercial contrast agents. Therefore, it can be considered as a promising candidate for T2 MRI contrast agent.

Introduction: Expansion of efficacious theranostic systems is of pivotal significance for medicine and human healthcare. Magnetic nanoparticles (MNPs) are known as drug delivery system and magnetic resonance imaging (MRI) contrast agent. MNPs as drug carriers have attracted significant attention because of the delivery of drugs loaded onto MNPs to solid tumors, maintaining them in the target site by an external electromagnetic field, and subsequently releasing drugs in a controlled manner. On the other hand, it is believed that MNPs possess high potential as MRI contrast agents. The aim of this work was to payload curcumin into dextran coated MNPs and investigate their potential as theranostic systems for controlled drug delivery and MRI imaging. Methods: MNPs were synthesized as a core and coated with dextran as polymeric shell to provide steric stabilization. Curcumin as anticancer drug was selected to be loaded into NPs. To characterize the synthesized NPs, various techniques (e.g., DLS, FESEM, FT-IR, XRD, and VSM) were utilized. In vitro drug release of curcumin was evaluated at 37˚C at the pH value of 5.4 and 7.4.The feasibility of employment of dextran coated MNPs as MRI contrast agents were also studied. Results: Formulations prepared from dextran coated MNPs showed high loading (13%) and encapsulation efficiency (95%). In vitro release study performed in the phosphate-buffered saline (PBS, pH= 7.4, 5.4) revealed that the dextran coated MNPs possess sustained release behavior at least for 4 days with the high extent of drug release in acidic media. Vibrating sample magnetometer (VSM) analysis proved the superparamagnetic properties of the dextran coated MNPs with relatively high-magnetization value indicating that they were sufficiently sensitive to external magnetic fields as magnetic drug carriers. Furthermore, dextran coated MNPs exhibited high potential as T2 contrast agents for MRI. Conclusion: Based on our findings, we propose the dextran coated MNPs as promising nanosystem for the delivery of various drugs such as curcumin and MRI contrast agent.

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The aim of this study is to synthesise superparamagnetic iron oxide nanoparticles conjugated with anti-epidermal growth factor receptor monoclonal antibody (ANTI-EGFR-SPION) and investigate its physicochemical characterisation and biocompatibility as a targeted magnetic resonance imaging (MRI) contrast agent for the EGFR-specific detection in EGFR expressing tumour cells. These particles employed biocompatible polymers, poly(D,L-lactide-co-glycolide) (PLGA) and polyethylene glycol aldehyde (PEG-aldehyde), to increase the half-life of particles in circulation and reduce their side effects. The Fe 3 O 4-loaded PLGA-PEG-aldehyde nanoparticles were prepared by a modified water-in-oil-in-water double emulsion method. The EGFR antibody was conjugated to the surface of SPIONs using the aldehyde-amine reaction. Synthesised conjugates (nanoprobes) were characterised using Fourier transform infrared spectrophotometry, dynamic light scattering, transmission electron microscopy images, and vibrating-sample magnetometery, and the results showed that the conjugation was successful. The mean diameter of nanoprobes was about 25 nm. These nanoprobes exhibited excellent water-solubility, stability, and biocompatibility. Meanwhile, MR susceptibility test proved that synthesised nanoprobes can be managed for negative contrast enhancement. The results of this study suggested the potential use of these nanoprobes for non-invasive molecular MRI in EGFR detection in the future.

Synthetic hydroxyapatite (HA) due to its high biocompatibility, anti-inflammatory properties, high stability, and a flexible structure in combination with magnetic nanoparticles has the strong potential to be used in modern medicine including tissue engineering, imaging, and drug delivery. Herein, a hydrothermal process was used to prepare magnetite nanoparticles dispersed on the hydroxyapatite nanorods with cetyltrimethylammonium bromide (CTAB) as a surfactant. Characterization study of the synthesized iron oxide-hydroxyapatite (IO-HA) nanocomposite was performed by FT-IR spectroscopy, X-ray powder diffraction, energy dispersive X-Ray analysis (EDX) for elemental mapping, transmission electron microscopy, and vibrating sample magnetometer. Then, the biocompatibility of the synthesized nanocomposite studied by 3-(4,5-dimethylthiazol-2-yl) -2,5-diphenyltetrazolium bromide (MTT) assay and hemocompatibility assay. Focus on this point, curcumin loaded IO-HA (Cur@IO-HA) was developed for exploring the pH-sensitivity of the drug carrier and then evaluating its cellular uptake. The in vitro efficacy of the synthesized nanocomposites as a magnetic resonance imaging (MRI) contrast agent was also investigated. Our results showed that IO-HA nanocomposite is non-cytotoxic and hemocompatible as well as a good pH-sensitive drug carrier and a favorable MRI T2 contrast agent. Comparing to the free curcumin, Cur@IO-HA displayed a good cellular uptake. Taking into account the above issues, IO-HA nanocomposite has the most potential for application as a theranostic MRI contrast agent.