EXTREMELY LOW FREQUENCY ELECTROMAGNETIC STIMULATION AS A TREATMENT FOR ISCHEMIC STROKE: INVOLVEMENT OF NITRIC OXIDE

Abstract

Mesoporous bioactive glasses (MBGs) are characterised by outstanding surface area and high porosity. These textural properties lead to significantly enhanced bioactivity compared with other glasses. Furthermore, this provides the possibility to use MBGs as local drug delivery systems, which combined with the release of therapeutic ions (e.g. Cu2+ and Co2+) gives opportunity for the development of mul-tifunctional biomaterials. Cu2+ and Co2+ ions released from bioactive glasses have been shown to induce formation of new blood vessels by mimicking hypoxia (low oxygen concentration). The aim of this work was to explore bioactivity and dissolution profiles of hypoxia-mimicking elements (Cu2+ and Co2+ ions) from MBGs and also to investigate the effect of these ions on the textural properties of MBGs. The Cu-and Co-doped MBGs with composition of 80SiO2-16CaO-4P2O5 (mol%) were produced using sol-gel technique coupled with evaporation-induced self-assembly process. CuO and CoO was substituted for CaO in the amounts of 1-5 mol%. MBGs were analysed using TEM, SAXS, and BET. MBGs were incubated in simulated body fluid (SBF) for 14 days. Changes in ion concentration in SBF were monitored using ICP-OES. FTIR and SEM/EDX were used to evaluate structural, morphological, and chemical changes of MBGs during incubation in SBF. The results indicated that Cu2+ and Co2+ ions affect bioactivity and dissolution of MBGs to a great extent. Furthermore, the presence of hypoxia-mimicking elements altered their textural properties (surface area, porosity, pore size and structure).