Preparation And Characterization Of The CPP Grafted PEC Film On Titanium Alloy

Objective Preparation and characterization of the CPP grafted PEC film on Ti alloy, in order to provide a potential application way to enhance the bioactivity of the Ti alloy.Methods The Ti alloy were firstly hydroxylated and modified by silane coupling agents, then the alginate and chitosan were fabricated by layer-by-layer self-assembly, finally casein phosphopeptide was grafted via amidation reaction, so the CPP-grafted polyelectrolyte complex film was prepared on the Ti alloy surfaces. The samples were mineralized in simulated body fluid, the surface composition, wettability, surface morphology and the ability of biomineralization were characterized by XPS, ATR-FTIR, FESEM, Contact angle measuring device,3D surface profilometer and XRD. At the same time, The samples and osteoblast were cultured in vitro, their cellular compatibility can be investigated.Results1XPS results showed that the Ti element disappeared and the C, N, O, P, Ca elements appeared in the polyelectrolyte layer and the polyelectrolyte complex film, showed that the Ti alloy substrates were completely covered and the surface chemical compositions has changed. ATR-FTIR results further confirmed that the group of polyelectrolyte layer included the carboxyl group, the hydroxyl group, the phosphate group grafted the casein phosphopeptide, showed that complex film was successfully prepared on Ti alloy. Compared with the control group, SEM results showed that the polyelectrolyte layer and the polyelectrolyte complex film formed the nano-pore structure, surface roughness were both increased, the surface wettability of the polyelectrolyte layer and the polyelectrolyte complex film were improved.2The experimental of biomineralization results showed that the hydroxyapatites were deposited on the surface of every group. The group of polyelectrolyte layer had good nano-porous structure, and included responsable active groups such as the carboxyl group, the hydroxyl group, the phosphate group grafted the casein phosphopeptide, therefore the polyelectrolyte complex film showed the density of hydroxyapatite. All this suggested that the CPP-grafted polyelectrolyte complex film was of better capacity of biomineralization.3Cellular compatibility tests showed that compared with the control group, the polyelectrolyte layer enhanced the adhesion and proliferation of osteoblast, the polyelectrolyte complex film significantly improved the growth of osteoblast (P＜O.05).Conclusion All above showed that by using the method of layer-by-layer self-assembly, the polyelectrolyte complex film successfully modified on the Ti alloy surface, improved the mineralization ability and cell compatibility of the Ti alloy. This method is effective for surface modification and presents potential clinical application value.