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Results are presented of studies of the physical-mechanical properties of silver-doped calcium phosphate coatings formed by radio-frequency magnetron sputtering on a surface of technically pure VT1-0 titanium and 12Cr18Ni10Ti stainless chromium-nickel surgical steel. The films have the nanocrystalline structure of hydroxyapatite with mean diameter of the coherently diffracting domains equal to 20-30 nm. It has been established that the configuration of the magnetic field of the magnetron has an effect on the roughness, thickness, and refractive index of the coatings. The thickness of the coatings and the refractive index vary within the ranges 300-700 nm and 1.68-1.80, respectively. The nanohardness of the coatings is within the range 4-7GPa, the modulus of elasticity of the coatings depends on the material of the substrate and is equal to 130-150 GPa for titanium and 170-200 GPa for steel. Sclerometric measurements of the coatings made it possible to establish a high adhesion strength of the coatings. [ABSTRACT FROM AUTHOR]

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As a measure of the prevention of implant associated infections, a number of strategies have been recently applied. Silver-containing materials possessing antibacterial activity as expected might have wide applications in orthopedics and dentistry. The present work focuses on the physico-chemical characterization of silver-containing hydroxyapatite (Ag-HA) coating obtained by radio frequency (RF) magnetron sputtering. Mechanochemically synthesized Ag-HA powder (Ca 10− x Ag x (PO 4 ) 6 (OH) 2− x , x = 1.5) was used as a precursor for sputtering target preparation. Morphology, composition, crystallinity, physico-mechanical features (Young's modulus and nanohardness) of the deposited Ag-HA coatings were investigated. The sputtering of the nanostructured multicomponent target at the applied process conditions allowed to deposit crystalline Ag-HA coating which was confirmed by XRD and FTIR data. The SEM results revealed the formation of the coating with the grain morphology and columnar cross-section structure. The EDX analysis confirmed that Ag-HA coating contained Ca, P, O and Ag with the Ca/P ratio of 1.6 ± 0.1. The evolution of the mechanical properties allowed to conclude that addition of silver to HA film caused increase of the coating nanohardness and elastic modulus compared with those of pure HA thin films deposited under the same deposition conditions. [ABSTRACT FROM AUTHOR]

In this work, we describe fabrication techniques used to prepare a multifunctional biocomposite based on a hydroxyapatite (HA) coating and silver nanoparticles (AgNPs). AgNPs synthesized by a wet chemical reduction method were deposited on Ti substrates using a dripping/drying method followed by deposition of calcium phosphate (CaP) coating via radio-frequency (RF) magnetron sputter-deposition. The negatively charged silver nanoparticles (zeta potential −21 mV) have a spherical shape with a metallic core diameter of 50 ± 20 nm. The HA coating was deposited as a dense nanocrystalline film over a surface of AgNPs. The RF-magnetron sputter deposition of HA films on the AgNPs layer did not affect the initial content of AgNPs on the substrate surface as well as NPs size and shape. SEM cross-sectional images taken using the backscattering mode revealed a homogeneous layer of AgNPs under the CaP layer. The diffraction patterns from the coatings revealed reflexes of crystalline HA and silver. The concentration of Ag ions released from the biocomposites after 7 days of immersion in phosphate and acetate buffers was estimated. The obtained results revealed that the amount of silver in the solutions was 0.27 ± 0.02 μg mL −1 and 0.54 ± 0.02 μg mL −1 for the phosphate and acetate buffers, respectively, which corresponded well with the minimum inhibitory concentration range known for silver ions in literature. Thus, this work establishes a new route to prepare a biocompatible layer using embedded AgNPs to achieve a local antibacterial effect. [ABSTRACT FROM AUTHOR]