Biological behavior of nano-sized zinc containing tricalcium phosphate coating on titanium alloys

To overcome certain problems encountered in osteointegration at the interface between the bone and implant, lack of cell proliferation and differentiation in the host tissue, we developed nanosized zinc-containing tricalcium phosphate and fluoridated hydroxyapatite (ZnTCP/FHA) coatings on Ti6V14V substrates using sol-gel dipping method. The effect of ZnTCP/FHA coating on cell proliferation and differentiation were evaluated using human osteoblast-like cells for understanding the role of the chemical composition of the implant surface in affecting the behavior of cells in contact with the material. Ti alloy with nanosized ZnTCP/FHA coating was compared with TCP/FHA coated and uncoated Ti alloy controls on cellular behavior by cell attachment, proliferation, alkaline phosphotatse (ALP) activity and scanning electron microscopy (SEM) analysis. These assays on zinc-containing coatings showed remarkably increased cell proliferation and higher levels of ALP activity as compared with controls. The results suggested that the use of zinc-containing TCP for the carrier and zinc-releasing can serve as a support for cell culture and promote cell proliferation and osteointegration. This investigation indicates the importance of the surface components such as zinc element in directing the cell response and hence tissue maintenance and remodeling.