abstract
We report on the effect of sodium on the structure, chemical degradation and bioactivity of glasses in the CaO-MgO-SiO2-P2O5-CaF2 system. The Si-29 and P-31 magic angle spinning-nuclear magnetic resonance spectroscopy of melt-quenched glasses with varying Na2O/MgO ratios exhibit a silicate glass network with the dominance of Q(2)(Si) units and phosphorus mainly forming orthophosphate species. Sodium incorporation in the glasses did not induce a significant structural change in the silicate network, while it did influence the phosphate environment due to its lower ionic field strength in comparison with that of magnesium. The apatite forming ability of glasses has been investigated by immersion of glass powders in simulated body fluid (SBF) for time durations varying between 1 h and 7 days while their chemical degradation has been studied in Tris-HCL in accordance with ISO-10993-14. Increasing Na+/Mg2+ ratio caused a decrease in the chemical durability of glasses and in the apatite forming ability especially during initial steps of interaction between glass and SBF solution. The cellular responses were observed in vitro on bulk glass samples using mouse-derived pre-osteoblastic MC3T3-E1 cell line. The preliminary study suggested that the increasing alkali-concentration in glasses led to cytotoxicity in the cell culture medium. (C) 2014 Elsevier B.V. All rights reserved.
keywords
FREE BIOACTIVE GLASSES; IN-VITRO; SPECTROSCOPY; ZINC
subject category
Materials Science
authors
Kansal, I; Reddy, A; Munoz, F; Choi, SJ; Kim, HW; Tulyaganov, DU; Ferreira, JMF
our authors
Allu Amarnath Reddy
PhD Student
Ishu Kansal
PhD Student
José Maria da Fonte Ferreira
Retired Professoracknowledgements
Ishu Kansal and A. A. Reddy are indebted to the Portuguese Foundation for Science and Technology (FCT) for the PhD grant References SFRH/BD/70917/2010 and SFRH/BD/89915/2012, respectively. Authors are thankful to CICECO, University of Aveiro for the facilities. The help of Lee HY and Oh SA in the cell culture studies is greatly acknowledged. This work was also supported in part by the grant from the Priority Research Centers Program (2009-0093829), and the National Research Foundation.