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Immune response to biomaterials, which is intimately related to their surface properties, can produce chronic inflammation and fibrosis, leading to implant failure. This study investigated the development of magnetic nanoparticles coated with silica and incorporating the anti-inflammatory drug naproxen, aimed at multifunctional biomedical applications. The synthesized nanoparticles were characterized using various techniques that confirmed the presence of magnetite and the formation of a silica-rich bioactive glass (BG) layer. In vitro studies demonstrated that the nanoparticles exhibited bioactive properties, forming an apatite surface layer when immersed in simulated body fluid, and biocompatibility with bone cells, with good viability and alkaline phosphatase activity. Naproxen, either free or encapsulated, reduced nitric oxide production, an inflammatory marker, while the BG coating alone did not show anti-inflammatory effects in this study. Overall, the magnetic nanoparticles coated with BG and naproxen showed promise for biomedical applications, especially anti-inflammatory activity in macrophages and in the bone field, due to their biocompatibility, bioactivity, and osteogenic potential. [ABSTRACT FROM AUTHOR]

Cancer is one of the deadliest diseases worldwide and has been responsible for millions of deaths. However, developing a satisfactory smart multifunctional material combining different strategies to kill cancer cells poses a challenge. This work aims at filling this gap by developing a composite material for cancer treatment through hyperthermia and drug release. With this purpose, magnetic nanoparticles were coated with a polymer matrix consisting of poly (L-co-D,L lactic acid-co-trimethylene carbonate) and a poly(ethylene oxide)–poly(propylene oxide)–poly(ethylene oxide) triblock copolymer. High-resolution transmission electron microscopy and selected area electron diffraction confirmed magnetite to be the only iron oxide in the sample. Cytotoxicity and heat release assays on the hybrid nanoparticles were performed here for the first time. The heat induction results indicate that these new magnetic hybrid nanoparticles are capable of increasing the temperature by more than 5 °C, the minimal temperature rise required for being effectively used in hyperthermia treatments. The biocompatibility assays conducted under different concentrations, in the presence and in the absence of an external alternating current magnetic field, did not reveal any cytotoxicity. Therefore, the overall results indicate that the investigated hybrid nanoparticles have a great potential to be used as carrier systems for cancer treatment by hyperthermia. [ABSTRACT FROM AUTHOR]

TMAOH-dispersed nanoparticles of magnetite were first prepared through the reduction-precipitation of ferric chloride with Na2SO3 and NH4OH. The TMAOH-dispersed (Fe3O4) magnetic nanoparticles were then surface-coated with poly(L-co-D,L lactic acid-co-trimethylene carbonate) (PLDLA-co-TMC) to obtain the corresponding hybrid system (Fe3O4/TMAOH/PLDLA-co-TMC). Samples of so prepared material were analyzed by Fourier-transform infrared spectroscopy (FTIR), powder X-ray diffraction (XRD), magnetization measurements up to 2.5 T, and Mössbauer spectroscopy. Results indicate that this magnetic iron oxide soon after the synthesis is structurally close enough to a typically pure stoichiometric magnetite. FTIR data support clears evidences confirming the efficiency of the solvent displacement method to assure coating the TMAOH-dispersed (Fe3O4) magnetic nanoparticles with the terpolymer while preserves the main chemical structural characteristic of the nanosized magnetite. [ABSTRACT FROM AUTHOR]

Abstract: The present work combines the results of two simple methods of determination of the Mn3+/Mn4+ ratio for La1−x Sr x MnO3±d powders, prepared by citrate route, in which the Sr content, x, varies from 0.16 to 0.40. The ratio Mn3+/Mn4+ was successfully estimated combining the results of Temperature Programmed Reduction (TPR) analysis and redox titration. Moreover, the possible perovskite chemical formulas were established and a direct relationship between the Sr content and the Mn4+ amount was found. Morphological analyses such as grain size and surface area are also presented to better characterize the powders. Gas adsorption by Brunauer–Emmett–Teller method (BET) and scanning electron microscopy (SEM) were used to evaluate the agglomeration degree of powders and showed the inhibitory influence of Sr content on the growth of crystallites. [Copyright &y& Elsevier]

Superparamagnetic iron oxides, as magnetite (Fe3O4) or maghemite (γ-Fe2O3), are primary materials with intrinsic properties that enable them, as single components or as special composites, to base advanced techniques in medical clinical practices, as a contrast agent in magnetic resonance imaging (MRI), as magnetically-induced hyperthermic heat generator, and as a magnetic guide to locally deliver drugs to specific sites in the human body. An interesting approach to developing nanoplatforms for those applications consists in manufacturing core@shell nanostructures, in which the precursor magnetic iron oxide (usually, magnetite) acts as a core, and an organic, or inorganic compound is used as a shell in a multifunctional composite. In this review, we report the current advances in the use of magnetite-based core@shell nanostructures, including Fe3O4@SiO2 and Fe3O4@polymers, in MRI, magnetic hyperthermia and drug delivery systems for diagnosis and therapy of tumor cells. The development of nanoplatforms for combined therapy and diagnostic (theranostic) is also addressed.