Effect of Mg2+, Sr2+, and Mn2+ on the Chemico-Physical and In Vitro Biological Properties of Calcium Phosphate Biomimetic Coatings

Department of Chemistry G. Ciamician, University of Bologna, 40126 Bologna, Italy.
Journal of inorganic biochemistry (Impact Factor: 3.44). 09/2009; 103(12):1666-74. DOI: 10.1016/j.jinorgbio.2009.09.009
Source: PubMed


We previously developed a calcium phosphate (CaP) calcifying solution that allows to deposit a uniform layer of nanocrystalline apatite on metallic implants in a few hours. In this work we modified the composition of the CaP solution by addition of Sr(2+), Mg(2+), and Mn(2+), in order to improve the biological performance of the implants. The results of the investigation performed on the coatings, as well as on the powders precipitated in the absence of the substrates, indicate that both Sr(2+) and Mg(2+) reduce the extent of precipitation, although they are quantitatively incorporated into the nanocrystalline apatitic phase. The inhibitory effect on deposition is much more evident for Mn(2+), which completely hinders the precipitation of apatite and yields just a small amount of amorphous phosphate relatively rich in manganese content. Human osteoblast-like MG-63 cells cultured on the different materials show that the Mg(2+) and Sr(2+) apatitic coatings promote proliferation and expression of collagen type I, with respect to bare Ti and to the thin layer of amorphous phosphate obtained in the presence of Mn(2+). However, the relatively high content of Mn(2+) in the phosphate has a remarkable beneficial effect on osteocalcin production, which is even greater than that observed for Sr(2+).

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    • "Positive effects of Mg enrichment of inorganic biomaterials in vitro have been reported. Mg-enriched HA has stimulated osteoblast adhesion [15] and proliferation [16] [17] [18]. Osteogenic differentiation of stem cells from both human bone marrow and human adipose tissue was superior on the Mg-containing bioceramic akermanite compared to the commonly used CaP bone replacement material beta-tricalcium phosphate (β-TCP) [19] [20] [21]. "
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    • "In literature, there are studies to improve the biological performance of HA with the substitution of various ions (Sr, Mn, Mg, among others) [11] [12]. Moreover, it has been reported that doping HA structures with different ions such as Mg 2+ could improve mineralization of calcified tissues and indirectly influence mineral metabolism [12] [13] [14] [15]. "
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