Bioactivity in SBF versus trace element effects: The isolated role of Mg 2+ and Zn 2+ in osteoblast behavior

• Published in: Materials science & engineering. C, Materials for biological applications Vol. 118; p. 111320
• Main Authors: de Araujo Bastos Santana, Lucas, Oliveira Junior, Paulo Henrique, Damia, Chantal, Dos Santos Tavares, Débora, Dos Santos, Euler Araujo
• Format: Journal Article
• Language: English
• Published: Netherlands 01-01-2021
• Subjects: Biocompatible Materials - pharmacology; Body Fluids; Ceramics; Glass; Humans; Osteoblasts; Silicon Dioxide; Trace Elements; Zinc; Osteoblast behavior; Bioglass; Kokubo assay; Magnesium; Zinc
• ISSN: 1873-0191

The bioactivity assay originally proposed by Kokubo is one of the most commonly used tests to indirectly evaluate the biocompatibility of bioactive glasses. However, extensive evidence has shown that trace elements present in biomaterials may stimulate cellular behavior in different ways even when no apatite formation is observed, i.e., in biomaterials with low or no bioactivity. To further elucidate this topic, we designed three different SiO
-rich bioglass compositions in which CaO was partially replaced by ZnO and MgO, two oxides known to affect bioactivity as well as osteoblastic behavior. The physicochemical changes induced by the presence of oxides and their effects on biological behavior, as well as the adhesion, proliferation and differentiation of human osteoblast-like osteosarcoma cells (MG-63), were followed by a bioactivity assay in simulated body fluid (SBF). The insertion of ZnO or MgO decreased the glass transition (T
) and crystallization (T
) temperatures as a function of the increase in nonbonding oxygens, which was directly reflected in the higher solubility. The release of Mg
ions from the MgO-containing samples inhibited the bioactivity in SBF, inducing high cell adhesion and proliferation and moderate ALP activity. The release of Zn
also inhibited the bioactivity in SBF but, in contrast to the release of Mg
, induced low cell adhesion and proliferation and high ALP activity compared to the control.