The use of porous titanium-based implant materials for bone contact has been gaining ground in recent years. Selective laser melting (SLM) is a rapid prototyping method by which porous implants with highly defined external dimensions and internal architecture can be produced. The coating of porous implants produced by SLM with ceramic layers based on calcium phosphate (CaP) remains relatively unexplored, as does the doping of such coatings with magnesium (Mg) to promote bone formation. In this study, Mg-doped coatings of the CaP types octacalcium phosphate and hydroxyapatite (HA) were deposited on such porous implants using the pulsed laser deposition method. The coated implants were subsequently implanted in a rabbit femoral defect model for 6 months. Uncoated implants served as a reference material. Bone-implant contact and bone volume in the region of interest were evaluated by histopathological techniques using a tri-chromatographic Masson-Goldner staining method and by microcomputed tomography (µCT) analysis of the volume of interest in the vicinity of implants. Histopathological analysis revealed that all implant types integrated directly with surrounding bone with ingrowth of newly formed bone into the pores of the implants. Biocompatibility of all implant types was demonstrated by the absence of inflammatory infiltration by mononuclear cells (lymphocytes), neutrophils, and eosinophils. No osteoclastic or foreign body reaction was observed in the vicinity of the implants. µCT analysis revealed a significant increase in bone volume for implants coated with Mg-doped HA compared to uncoated implants.
In this paper chemical modification of a poly(vinylidene fluoride) surface by extreme ultraviolet (EUV) irradiation in a presence of ionized nitrogen was demonstrated for the first time. Nitrogen gas, injected into an interaction region, was ionized and excited by the EUV radiation from a laser-plasma source. The ionization degree and excited states of nitrogen were investigated using EUV spectrometry and the corresponding spectra are presented. Chemical mod- ification of polymer after combined EUV and ionized nitrogen treatment was investigated using X-ray photoelectron spectroscopy. A significant contribution of nitrogen atoms in near-surface layer of the polymer after the treatment was demonstrated.Polymers are widely used in industry because of good mechanical properties and their resistance to environmental factors. For some applications, however, surface properties of polymers must be modified. The modification may concern hydrophobicity, wettability, adsorption, adhesion, optical or other surface properties and is associated with some changes in physicochemical structure of the near-surface layer. Different methods can be employed for surface structuring, including chemical [1], plasma [2], or radiation treatment. In the last case, ultraviolet (UV) lamps or UV lasers are mainly used [3][4][5]. Photons emitted from these sources can excite electrons from the valence band of polymer materials. Molecular electronic structure of the materials has some resonances, hence, excitation rate depends on energy of the irradiating photons and strongly influences the absorption depth. The excited states can relax through radiative or non-radiative processes. In case of polymers one of the possible radiationless channels corresponds to bond breaking of the polymer chain. This can result in formation of volatile fractions or in changes in chemical structure and composition of the polymer molecules. Some volatile fractions are released from irradiated layer resulting in smooth ablation or modification of the surface morphology due to a preferential dry etching of an amorphous polymer. For some applications incorporation of some functional groups into the polymer molecules is necessary. In such cases irradiation is being performed in a reactive atmosphere [4].
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