No abstract

Several laboratories had tested bioactivity of the materials in commercially available solution DMEM (Dulbecco's Modified Eagle's Medium) that is normally used for cultivation of cell cultures. The objective of this work was to find out whether it is possible to replace TRIS-buffered SBF currently used for bioactivity tests with the non-buffered DMEM solution. To understand the role of the organic part of the DMEM solution in the process of crystallization, we have prepared non-buffered solution simulating only its inorganic part (identified as I-solution). It was found that under static-dynamic test conditions calcite (CaCO3) and the amorphous phase of calcium phosphate (ACP) formed on the surface of the glass-ceramic (45S5 bioactive glass based) scaffold exposed to both solutions. Additionally, halite (NaCl) formed at the beginning of exposure to DMEM. Hydroxyapatite phase was not detected on the surface in either non-buffered solution. Organic components contained in the DMEM solution failed to prevent formation of crystalline phases. The present results indicate that it is not recommendable to use DMEM for bioactivity tests of glass-ceramic materials due to its low concentration of Ca2+ ions, high concentration of HCO 3- ions and the necessity to maintain sterile environment during the test. © 2014 the Partner Organisations

Bioactive glasses are used to regenerate bone, and when developing new compositions, in vitro cell culture studies are key. As test parameters vary widely, this review provides an overview, helping researchers to select the appropriate ones.

When evaluating new bioactive glass compositions for their suitability as a biomaterial, one of the first steps is the study of their behavior in contact with aqueous solutions. Ion release, pH changes, and apatite precipitation are investigated during immersion experiments, and a wide variety of solutions is used, including simulated body fluid, Tris buffer solution, various cell culture medium formulations or deionized water. This paper reviews the different parameters used for immersion experiments on bioactive glasses. Results show that, depending on solution composition, pH, and buffering capacity, the experimental outcome is likely to vary. In addition, bioactive glass particle size and solution volume/glass surface area ratio affect the resulting ion concentration in solution, and, thus, the rate at which apatite is formed. It is, therefore, important to consider these effects when planning experiments, interpreting results or comparing the results of experiments performed in different laboratories.