Síntese, caracterização, citotoxicidade e imunomodulação de vidros bioativos dopados com prata em leucócitos humanos

Abstract

Bioactive glasses (BG) has application in tissue engineering for bone regeneration, coating for implants and stimulatory of wound healing. BG can be conjugated to antimicrobial ions like silver (Ag) giving it antibacterial activity. Once the immunomodulatory activity of bioactive glasses doped with silver was not investigated before, the aim of this work was to evaluate the cytotoxic and immunomodulatory effect of BG and silver-doped bioactive silica (BGAg). BG and BGAg samples belonging to the system 58SiO2∙(36-x)CaO·6P2O5·xAg2O, where x = 0 and 1 mol%, respectively, were synthesized via sol–gel method, and characterized by Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), Surface-enhanced Raman Spectroscopy (Raman-SERS), Differential Thermal Analysis (DTA), Thermal Gravimetric Analysis (TGA) and X-ray diffraction (XRD). Cytotoxicity, cytokine modulation and oxidative stress were performed in human peripheral blood mononuclear cells (PBMCs) and polymorphonuclear neutrophils (PMNs) cultures. Microscopy characterization showed particles ≤74 μm with irregular and porous surface. RAMAN-SERS analyses confirmed silver inclusion within BGAg samples. PBMC viability in presence of BG or BGAg was dose-dependent. Samples of the BGAg presented high toxicity (LC50 = 0.005%) relative to BG (LC50 = 0.106%) against PBMCs. The glasses did not changed cytokines and Reactive oxygen species (ROS) basal secretion profiles. Therefore, BG samples decrease ROS’s levels when coincubated with positive control. Overall, Ag-modified glass particles had impact on the morphology or physical properties, although ion incorporation has increased its cytotoxicity.