Loading with Biomolecules Modulates the Antioxidant Activity of Cerium-Doped Bioactive Glasses

Bifunctional mesoporous glasses for bone tissue engineering: Biological effects of doping with cerium and polyphenols in 2D and 3D in vitro models

This study evaluates the cytocompatibility of cerium-doped mesoporous bioactive glasses (Ce-MBGs) loaded with polyphenols (Ce-MBGs-Poly) for possible application in bone tissue engineering after tumour resection. We tested MBGs powders and pellets on 2D and 3D in vitro models using human bone marrow-derived mesenchymal stem cells (hMSCs), osteosarcoma cells (U2OS), and endothelial cells (EA.hy926). Promisingly, at a low concentration in culture medium, Poly-loaded MBGs powders containing 1.2 mol% of cerium inhibited U2OS metabolic activity, preserved hMSCs viability, and had no adverse effects on EA.hy926 migration. Moreover, the study discussed the possible interaction between cerium and Poly, influencing anti-cancer effects. In summary, this research provides insights into the complex interactions between Ce-MBGs, Poly, and various cell types in distinct 2D and 3D in vitro models, highlighting the potential of loaded Ce-MBGs for post-resection bone tissue engineering with a balance between pro-regenerative and anti-tumorigenic activities.

Extraction, purification and in vitro assessment of the antioxidant and anti-inflammatory activity of policosanols from non-psychoactive Cannabis sativa L

Policosanols (PCs) are bioactive compounds extracted from different natural waxes. In this work, the purification, characterization and assessment of the antioxidant and anti-inflammatory activity was carried out on PCs from an innovative source, i.e. a waxy material from supercritical-fluid extraction (SFE) of non-psychoactive Cannabis sativa L. (hemp) inflorescences. Starting from this material, PCs were obtained by microwave-assisted trans-esterification and hydrolysis, followed by preparative liquid chromatography under normal phase conditions. The purified product was characterized using high-performance liquid chromatography (HPLC) with an evaporative light scattering detector (ELSD). In vitro cell-free and cell-based antioxidant and anti-inflammatory assays were then performed to assess their bioactivity. HPLC-ELSED analysis of the purified mixture from hemp wax revealed C26OH and C28OH as the main compounds. In vitro assays indicated an inhibition of intracellular reactive oxygen species (ROS) production, a reduction of nuclear factor kappa B (NF-κB) activation and of the activity of the neutrophil elastase. Immunoblotting assays allowed us to hypothesize the mechanism of action of the compounds of interest, given the higher levels of MAPK-activated protein kinase 2 (MK2) and heme oxygenase-1 (HO-1) protein expression in the PC pretreated HaCaT cells. In conclusion, even if more research is needed to unveil other molecular mechanisms involved in hemp PC activity, the results of this work suggest that these compounds may have potential for use in oxinflammation processes.

The unexplored role of alkali and alkaline earth elements (ALAEs) on the structure, processing, and biological effects of bioactive glasses

Bioactive glass has been employed in several medical applications since its inception in 1969. The compositions of these materials have been investigated extensively with emphasis on glass network formers, therapeutic transition metals, and glass network modifiers. Through these experiments, several commercial and experimental compositions have been developed with varying chemical durability, induced physiological responses, and hydroxyapatite forming abilities. In many of these studies, the concentrations of each alkali and alkaline earth element have been altered to monitor changes in structure and biological response. This review aims to discuss the impact of each alkali and alkaline earth element on the structure, processing, and biological effects of bioactive glass. We explore critical questions regarding these elements from both a glass science and biological perspective. Should elements with little biological impact be included? Are alkali free bioactive glasses more promising for greater biological responses? Does this mixed alkali effect show increased degradation rates and should it be employed for optimized dissolution? Each of these questions along with others are evaluated comprehensively and discussed in the final section where guidance for compositional design is provided.

Advanced Biological Applications of Cerium Oxide Nanozymes in Disease Related to Oxidative Damage

Due to their excellent catalytic activities, cerium oxide nanoparticles have promise as biological nanoenzymes. A redox reaction occurs between Ce3+ ions and Ce4+ ions during which they undergo conversion by acquiring or losing electrons as well as forming oxygen vacancies (or defects) in the lattice structure, which can act as antioxidant enzymes and simulate various enzyme activities. A number of cerium oxide nanoparticles have been engineered with multienzyme activities, including catalase, superoxide oxidase, peroxidase, and oxidase mimetic properties. Cerium oxide nanoparticles have nitric oxide radical clearing and radical scavenging properties and have been widely used in a number of fields of biology, including biomedicine, disease diagnosis, and treatment. This review provides a comprehensive introduction to the catalytic mechanisms and multiple enzyme activities of cerium oxide nanoparticles, along with their potential applications in the treatment of diseases of the brain, bones, nerves, and blood vessels.

Ce-MBGs Loaded with Gentamicin: Characterization and In Vitro Evaluation

Mesoporous Bioactive Glasses (MBGs) are biomaterials widely used in tissue engineering, particularly for hard tissue regeneration. One of the most frequent postoperative complications following a biomaterial surgical implant is a bacterial infection, which usually requires treatment by the systemic administration of drugs (e.g., antibiotics). In order to develop biomaterials with antibiotic properties, we investigated cerium-doped MBGs (Ce-MBGs) as in situ-controlled drug delivery systems (DDSs) of gentamicin (Gen), a wide spectrum antibiotic commonly employed against bacteria responsible of postoperative infections. Here we report the optimization of Gen loading on MBGs and the evaluation of the antibacterial properties and of retention of bioactivity and antioxidant properties of the resulting materials. The Gen loading (up to 7%) was found to be independent from cerium content, and the optimized Gen-loaded Ce-MBGs retain significant bioactivity and antioxidant properties. The antibacterial efficacy was verified up to 10 days of controlled release. These properties make Gen-loaded Ce-MBGs interesting candidates for simultaneous hard tissue regeneration and in situ antibiotic release.

Antioxidant Effects of Bioactive Glasses (BGs) and Their Significance in Tissue Engineering Strategies

Elevated levels of oxidative stress are usually observed following injuries, leading to impaired tissue repair due to oxidation-related chronic inflammation. Several attempts have been made to manage this unfavorable situation, and the use of biomaterials with antioxidant activity is showing great promise in tissue engineering and regenerative medicine approaches. Bioactive glasses (BGs) are a versatile group of inorganic substances that exhibit an outstanding regenerative capacity for both hard and soft damaged tissues. The chemical composition of BGs provides a great opportunity for imparting specific biological activities to them. On this point, BGs may easily become antioxidant substances through simple physicochemical modifications. For example, particular antioxidant elements (mostly cerium (Ce)) can be added to the basic composition of the glasses. On the other hand, grafting natural antioxidant substances (e.g., polyphenols) on the BG surface is feasible for making antioxidant substitutes with promising results in vitro. Mesoporous BGs (MBGs) were demonstrated to have unique merits compared with melt-derived BGs since they make it possible to load antioxidants and deliver them to the desired locations. However, there are actually limited in vivo experimental studies on the capability of modified BGs for scavenging free radicals (e.g., reactive oxygen species (ROS)). Therefore, more research is required to determine the actual potential of BGs in decreasing oxidative stress and subsequently improving tissue repair and regeneration. The present work aims to highlight the potential of different types of BGs in modulating oxidative stress and subsequently improving tissue healing.