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In this study, the surface properties and corrosion behavior of a titanium sample modified with an electrochemically formed oxide layer (Ti‖TiO2) and Ti‖TiO2 sample coated with poly(N-ethyl-4-vinylpyridinium) cations (PE4VP) were studied. It was shown, by means of atomic force microscopy and ellipsometry, that the Ti‖TiO2 surface is very flat with an average roughness of only 3.4 nm and an oxide layer thickness of 16.1 nm. The inner surface potential of the Ti‖TiO2 sample as a function of pH and concentration of sodium chloride was measured using the constructed Ti‖TiO2 electrode. In order to improve the corrosion protective effectiveness of the surface coating, the process parameter conditions for strong poly(N-ethyl-4-vinylpyridinium) cation optimal adsorption on the electrochemically formed TiO2 oxide layer were determined using ellipsometry, tensiometry, and atomic force microscopy. The effect of adsorption of PE4VP cations on the inner surface potential and corrosion protection effectiveness of the TiO2 and TiO2-PE4VP coatings was examined. The electrochemical behaviour and corrosion properties of an unmodified titanium surface, titanium surface modified with an electrochemically formed TiO2 and subsequently modified with a PE4VP polyelectrolyte-based coating were examined by means of electrochemical impedance spectroscopy. Increased polarization resistance values and high corrosion protection effectiveness after surface modification with the PE4VP coating indicate the formation of a highly protective coating with high corrosion resistance imparted to the underlying titanium. The results presented here provide an insight into the optimization of strong polyelectrolyte cation adsorption process parameters and demonstrate that application of a PE4VP coating is a suitable method for surface modification of titanium to enhance corrosion protection in an aggressive environment. [ABSTRACT FROM AUTHOR]

Although titanium and its alloys are widely used as dental implants, they cannot induce the formation of new bone around the implant, which is a basis for the functional integrity and long-term stability of implants. This study focused on the functionalization of the titanium/titanium oxide surface as the gold standard for dental implants, with electrospun composite fibers consisting of polyvinylpyrrolidone and Ca2+ ions. Polymer fibers as carriers of Ca2+ ions should gradually dissolve, releasing Ca2+ ions into the environment of the implant when it is immersed in a model electrolyte of artificial saliva. Scanning electron microscopy, energy dispersive X-ray spectroscopy and attenuated total reflectance Fourier transform infrared spectroscopy confirmed the successful formation of a porous network of composite fibers on the titanium/titanium oxide surface. The mechanism of the formation of the composite fibers was investigated in detail by quantum chemical calculations at the density functional theory level based on the simulation of possible molecular interactions between Ca2+ ions, polymer fibers and titanium substrate. During the 7-day immersion of the functionalized titanium in artificial saliva, the processes on the titanium/titanium oxide/composite fibers/artificial saliva interface were monitored by electrochemical impedance spectroscopy. It can be concluded from all the results that the composite fibers formed on titanium have application potential for the development of osteoinductive and thus more biocompatible dental implants. [ABSTRACT FROM AUTHOR]

The surface modification of dental implants plays an important role in establishing a successful interaction of the implant with the surrounding tissue, as the bioactivity and osseointegration properties are strongly dependent on the physicochemical properties of the implant surface. A surface coating with bioactive molecules that stimulate the formation of a mineral calcium phosphate (CaP) layer has a positive effect on the bone bonding process, as biomineralization is crucial for improving the osseointegration process and rapid bone ingrowth. In this work, the spontaneous deposition of calcium phosphate on the titanium surface covered with chemically stable and covalently bound alendronate molecules was investigated using an integrated experimental and theoretical approach. The initial nucleation of CaP was investigated using quantum chemical calculations at the density functional theory (DFT) level. Negative Gibbs free energies show a spontaneous nucleation of CaP on the biomolecule-covered titanium oxide surface. The deposition of calcium and phosphate ions on the alendronate-modified titanium oxide surface is governed by Ca2+–phosphonate (-PO3H) interactions and supported by hydrogen bonding between the phosphate group of CaP and the amino group of the alendronate molecule. The morphological and structural properties of CaP deposit were investigated using scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction and attenuated total reflectance Fourier transform infrared spectroscopy. This integrated experimental–theoretical study highlights the spontaneous formation of CaP on the alendronate-coated titanium surface, confirming the bioactivity ability of the alendronate coating. The results provide valuable guidance for the promising forthcoming advancements in the development of biomaterials and surface modification of dental implants. [ABSTRACT FROM AUTHOR]