Publication details

Authors: Singh, S. S.; Roy, A.; Lee, B.; Kumta, P. N. 
Title: Aqueous deposition of calcium phosphates and silicate substituted calcium phosphates on magnesium alloys 
Type: Journal Article 
Publisher: Materials Science and Engineering B-Advanced Functional Solid-State Materials 
Year: 2011 
Volume: 176 
Issue: 20 
Start Page: 1695 
End Page: 1702 
DOI: 10.1016/j.mseb.2011.08.005 
Abstract: Attempts were made to deposit homogeneous films of calcium phosphates (CaPs) on two magnesium alloy systems, AZ31 and Mg-4Y. through an aqueous phosphating bath method. The deposition of silicate substituted CaPs by this aqueous method was also explored as silicate substitution is believed to increase the bioactivity of Caps. The effect of doped and undoped coatings on the in vitro degradation and bioactivity of both alloy systems was studied. FTIR and EDX confirmed the deposition of Ca, P. and Si on both alloys and the coatings appeared to consist primarily biphasic mixtures of hydroxyapatite and beta-TCP. These largely inhomogeneous coatings, as observed by SEM, were not shown to have any significant effect on maintaining the physiological pH of the culture medium in comparison to the uncoated samples, as the pH remained approximately in the 8.4-8.7 range. Interestingly, despite similar pH profiles between the coated and uncoated samples, CaP coatings affected the degradation of both alloys. These doped and undoped calcium phosphate coatings were observed to decrease the degradation of AZ31 whereas they increased the degradation of Mg-4Y. In vitro studies on cell attachment using MC3T3-E1 mouse osteoblasts showed that between the uncoated alloys, Mg-4Y appeared to be the more biocompatible of the two. Silicate substituted CaP coatings were observed to increase the cell attachment on AZ31 compared to bare and undoped CaPs coated samples, but did not have as great of an effect on increasing cell attachment on Mg-4Y. (C) 2011 Elsevier B.V. All rights reserved. 
Keywords: magnesium, calcium phosphates, aqueous, in-vitro, surface-roughness, cement, az31, hydroxyapatite, proliferation, degradation, adhesion, behavior