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.

Cobalt-containing bioactive glass mimics vascular endothelial growth factor A and hypoxia inducible factor 1 function.

Bioactive glasses (BGs) have shown great potential for tissue regeneration and their composition flexibility allows the incorporation of different ions with physiological activities and therapeutic properties in the glass network. Among the many ions that could be incorporated, cobalt (Co) is a significant one, as it mimics hypoxia, triggering the formation of new blood vessels by the vascular endothelial growth factor A (VEGFA), due to the stabilizing effect on the hypoxia inducible factor 1 subunit alpha (HIF1A), an activator of angiogenesis-related genes, and is therefore of great interest for tissue engineering applications. However, despite its promising properties, the effects of glasses incorporated with Co on angiogenesis, through human umbilical cord vein endothelial cells (HUVECs) studies, need to be further investigated. Therefore, this work aimed to evaluate the biocompatibility and angiogenic potential of a new sol-gel BG, derived from the SiO2 -CaO-P2 O5 -CoO system. The structural evaluation showed the predominance of an amorphous glass structure, and the homogeneous presence of cobalt in the samples was confirmed. in vitro experiments showed that Co-containing glasses did not affect the viability of HUVECs, stimulated the formation of tubes and the gene expression of HIF1A and VEGFA. in vivo experiments showed that Co-containing glasses stimulated VEGFA and HIF1A expression in blood vessels and cell nuclei, respectively, in the deep dermis layer of the dorsal region of rats, featuring considerable local stimulation of the angiogenesis process due to Co-release. Co-containing glasses showed therapeutic effect, and Co incorporation is a promising strategy for obtaining materials with superior angiogenesis properties for tissue engineering applications.

The proteolytic fraction from Vasconcellea cundinamarcensis accelerates wound healing after corneal chemical burn in rabbits.

INTRODUCTION: Chemical ocular burns are among the most frequently eye-related injuries, which require immediate and intensive evaluation and care since they may lead to potential complications such as superinfection, corneal perforation, and blindness.Vasconcellea cundinamarcensis, a species from Caricaceae family, contains highly active proteolytic enzymes in its latex that show healing activity in animal models bearing lesions of different etiologies. METHODS: We evaluate the ocular toxicity of the proteolytic fraction from V. cundinamarcensis (P1G10) by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and Hen's Egg Test-Chorioallantoic Membrane test. The corneal healing property of P1G10 was studied by the ethanol-chemical burn in the rabbit's eyes. RESULTS: P1G10 is safe for ocular administration, except when administrated at 10µg/mL. P1G10 at 1µg/mL accelerates the corneal re-epithelization achieving complete wound closure after 72h of chemical burn. Also, P1G10 modulated the inflammatory response and controlled the arrangement of collagen fibers in the stroma, demonstrating its potential corneal healing properties. CONCLUSIONS: Our work was the first one to evaluate the ophthalmic application of P1G10. Here we demonstrated that P1G10 is suitable for ocular administration and it has a promising corneal healing activity which may emerge as a new pharmacological tool to the development of a new drug for ocular surface chemical injuries in the future.

Influence of recovering collagen with bioactive glass on osteoblast behavior.

Bioactive ceramics have interesting properties from the biological standpoint, but their effects on cellular events remain partially unknown. In the current work, we investigated cellular viability, proliferation, and metabolic activity of rat primary osteoblasts in contact with four different samples: type I collagen, bioactive glass-coated collagen (GC), and both samples submitted to immersion for 5 days in a simulated body fluid. The bioactive glass coating was obtained from a sol-gel process. The cell viability, the alkaline phosphate, the collagen secretion, and the nitric oxide production by osteoblast were measured after 72 h of incubation in the presence of the samples. The GC that was immersed for 5 days in a simulated body fluid solution showed an increase in osteoblast viability and proliferation when it was compared with control and the other samples.

Bombesin Encapsulated in Long-Circulating pH-Sensitive Liposomes as a Radiotracer for Breast Tumor Identification.

Bombesin (BBN) is a tetradecapeptide that binds specifically to gastrin-releasing peptide receptors in humans. These receptors are over-expressed in several forms of cancer; radiolabeled BBN could therefore be used to detect such cancers. However, the degradation of peptides is a critical issue in the development of tumor tracers. Liposomes can be used to overcome this problem and improve the uptake of tracers by tumors. Therefore, the purpose of this study was to prepare and characterize long-circulating and pH-sensitive liposomes (SpHL) containing 99mTc-HYNIC-ßAla-Bombesin(7-14) (99mTc-BBN(7-14). In addition, the ability of this system to identify human breast cancer tissue was evaluated using biodistribution studies and scintigraphic images. Long-circulating and pH-sensitive liposomes (SpHL) were prepared and freeze-dried in the presence of cryoprotectants (glucose, mannitol, and trehalose). They were subsequently reconstituted with a solution of 99mTc-HYNIC-ßAla-Bombesin(7-14) (99mTc-BBN(7-14)). The liposomes were evaluated for size, encapsulation percentage, radiotracer leakage, and storage stability. In addition, in vivo studies were performed in breast tumor-bearing nude mice. Liposomes in the presence of glucose (SpHLG), exhibited a mean diameter of 164.5 ± 6.5 nm and exhibited a 99mTc-BBN(7-14) encapsulation percentage of 30%. In addition, they remained highly stable for up to 120 days of storage. SpHLG- 99mTc-BBN(7-14) showed longer blood circulation than free 99mTc-BBN(7-14), did. The tumor-to-muscle and tumor-to-blood ratios for SpHLG-99mTc-BBN(7-14 were high at 4 h post-injection (9.31%ID/g and 7.93%ID/g, respectively). Furthermore, scintigraphic images revealed a strong signal in the tumor area, indicating tumor specificity of SpHLG-99mTc-BBN(7-14). In summary, SpHLG-99mTc-BBN(7-14) presented characteristics suitable for a diagnostic agent, and is a potential tool for tumor identification.