Síntese, caracterização e avaliação funcional de compósitos à base de vidro bioativo funcionalizados com extrato de Dysphania ambrosioides

Abstract

Bioactive glasses have gained prominence in regenerative medicine due to their ability to interact with biological tissues, induce hydroxyapatite formation, and act as systems for the controlled release of bioactive agents. In this context, the functionalization of these materials with natural products in composite formulations has emerged as a promising strategy to incorporate antimicrobial, anti-inflammatory, and antioxidant properties relevant to tissue repair. Among the species of interest, Dysphania ambrosioides (mastruz) has a broad ethnopharmacological background, together with preclinical evidence of antimicrobial, anti inflammatory, and wound-healing activity, which supports its investigation as a functionalizing agent for glass-based composites. Thus, this dissertation aimed to synthesize and evaluate the physicochemical, antimicrobial, and anti-inflammatory properties of borate-based bioactive glass composites functionalized with D. ambrosioides extract. The dissertation is organized into two chapters. Chapter 1 presents a scoping review on the biological potential of bioactive glasses functionalized with natural products in preclinical models, including 24 studies. Overall, functionalization favored the controlled release of bioactive substances, accelerated hydroxyapatite formation, and added antioxidant, antimicrobial, and immunomodulatory properties, without compromising cytocompatibility in most studies. However, important methodological heterogeneity was observed among the analyzed studies. Chapter 2 describes the development of bioactive glass-based composites functionalized with hydroethanolic extract of D. ambrosioides at concentrations of 6% and 12%, compared with the blank composite (0%). The extract showed 86.1 ± 8.88 mg GAE·g⁻¹ of total phenolic compounds and 42.49 ± 0.89 mg QE·g⁻¹ of total flavonoids, in addition to a chromatographic profile compatible with a kaempferol diglycoside. The analytical curve in PBS showed excellent linearity (R² = 0.999). In the release assays, there was a rapid initial release between 2 and 8 hours, more pronounced in the 12% formulation. In SBF, the materials promoted a gradual increase in pH and greater mass loss in the functionalized groups. The diffractograms indicated a predominantly amorphous matrix, with a reflection suggestive of hydroxyapatite at approximately 42° (2θ). Biologically, the composites maintained cell viability ≥ 80%, reduced nitric oxide production, and showed antibacterial activity against Staphylococcus aureus.