Abstract
CaSiO3 has been used a potential bioactive material for bone regeneration. A drawback of the CaSiO3 ceramics is that they possess high dissolution rate of Ca ions leading to a high pH value environment [1], which can disadvantage cell growth. Zn can enhance osteoconductivity of CaP ceramics and stimulate bone formation [2]. The aims of this study are:
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In situ preparation and optimization of Zn-CaSiO3 ceramics by the evaluating of physical and chemical properties, osteoblast and osteoclast behavior;
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Sol-gel coating the optimized hardystonite (HT, Ca2ZnSi2O7) on Ti-6Al-4V.
Zn-CaSiO3 ceramics containing zero, ten, 20 and 50-mol% of Zn were sintered at 1260 °C. The dissolution and apatite formation ability were evaluated by soaking in simulated body fluids. Attachment, proliferation and differentiation of human primary bone-derived cells (HBDC) on ceramic disks were evaluated. Human monocytes isolated from buffy coats were differentiated into mature and functional osteoclast (OC) by culturing them for 21 days on ceramic disks. Then, the optimized HT (50%Zn-CaSiO3) coating on Ti-6Al-4V was prepared by sol-gel spinning method.
The incorporation of Zn in CaSiO3 resulted in part of new phase formation (HT) formation in Zn-Ca-Si ceramics. When adding 50 mol% of Zn, only pure HT phase existed.
The incorporation of Zn in CaSiO3 decreased the dissolution and pure 50 mol% of Zn (HT ceramics) resulted in the lowest dissolution.
Zn-CaSiO3 ceramics with different Zn contents supported HBDC attachment. With the increase of Zn contents, HBDC proliferation and differentiation improved. The surface roughness of Sol-gel HT coating is about 0.49 μm. The thickness of coating is about 1 μm. HT coating has a similar dissolution kinetics and stability with hydroxyapatite coating.
Zn decreases the dissolution in Zn-Ca-Si ceramics and enhances HBDC proliferation and differentiation. The optimized HT ceramics (50mol% Zn) support OC resorption and can be used for a stable biomedical coating application.
Correspondence should be addressed to David Haynes, PhD, Senior Lecturer, President ANZORS, at Discipline of Pathology, School of Medical Sciences, University of Adelaide, SA, 5005, Australia
