Novel Fe3O4 Nanoparticles with Bioactive Glass-Naproxen Coating: Synthesis, Characterization, and In Vitro Evaluation of Bioactivity.

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.

Heating Capacity and Biocompatibility of Hybrid Nanoparticles for Magnetic Hyperthermia Treatment.

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.

Unveiling the Effects of Rare-Earth Substitutions on the Structure, Mechanical, Optical, and Imaging Features of ZrO2 for Biomedical Applications.

The impact of selective rare-earth (RE) additions in ZrO2-based ceramics on the resultant crystal structure, mechanical, morphological, optical, magnetic, and imaging contrast features for potential applications in biomedicine is explored. Six different RE, namely, Yb3+, Dy3+, Tb3+, Gd3+, Eu3+, and Nd3+ alongside their variations in the dopant concentrations were selected to accomplish a wide range of combinations. The experimental observations affirmed the roles of size and dopant concentration in determining the crystalline phase behavior of ZrO2. The significance of tetragonal ZrO2 (t-ZrO2) → monoclinic ZrO2 degradation is evident with 10 mol % of RE substitution, while RE contents in the range of 20 and 40 mol % ensured either t-ZrO2 or cubic ZrO2 (c-ZrO2) stability until 1500 °C. High RE content in the range of 80-100 mol % still confirmed the structural stability of c-ZrO2 for lower-sized Yb3+, Dy3+, and Tb3+, while the c-ZrO2 → RE2Zr2O7 phase transition becomes evident for higher-sized Gd3+, Eu3+, and Nd3+. A steady decline in the mechanical properties alongside a quenching effect experienced in the emission phenomena is apparent for high RE concentrations in ZrO2. On the one hand, the paramagnetic characteristics of Dy3+, Tb3+, Gd3+, and Nd3+ fetched excellent contrast features from magnetic resonance imaging analysis. On the other hand, Yb3+ and Dy3+ added systems exhibited good X-ray absorption coefficient values determined from computed tomography analysis.

Formation Mechanisms in ß-Ca3(PO4)2-ZnO Composites: Structural Repercussions of Composition and Heat Treatments.

Composites with varied proportions of ß-Ca3(PO4)2 and ZnO were obtained through an in situ aqueous precipitation method under slightly basic (pH ≈ 8) conditions. The formation of ß-Ca3(PO4)2 phase starts at an early heat-treatment stage (∼800 °C) and incorporates Zn2+ ions at both Ca2+(4) and Ca2+(5) sites of the lattice up to its occupancy saturation limit. The incorporation of Zn2+ in the ß-Ca3(PO4)2 lattice enhances its thermal stability delaying the allotropic ß-Ca3(PO4)2→α-Ca3(PO4)2 phase transformation. The excess zinc beyond the occupancy saturation limit precipitates as Zn(OH)2 and undergoes dehydroxylation to form ZnO at elevated temperatures. The presence of ZnO in the ß-Ca3(PO4)2 matrix yields denser microstructures and thus improves the mechanical features of sintered composites up to an optimal ZnO concentration beyond which it tends to exert an opposite effect.