Calcium phosphate bone cements (CPCs) with antibacterial properties are demanded for clinical applications. In this study, we demonstrated the use of a relatively simple processing route based on preparation of silver-doped CPCs (CPCs-Ag) through the preparation of solid dispersed active powder phase. Real-time monitoring of structural transformations and kinetics of several CPCs-Ag formulations (Ag = 0 wt %, 0.6 wt % and 1.0 wt %) was performed by the Energy Dispersive X-ray Diffraction technique. The partial conversion of β-tricalcium phosphate (TCP) phase into the dicalcium phosphate dihydrate (DCPD) took place in all the investigated cement systems. In the pristine cement powders, Ag in its metallic form was found, whereas for CPC-Ag 0.6 wt % and CPC-Ag 1.0 wt % cements, CaAg(PO₃)₃ was detected and Ag (met.) was no longer present. The CPC-Ag 0 wt % cement exhibited a compressive strength of 6.5 ± 1.0 MPa, whereas for the doped cements (CPC-Ag 0.6 wt % and CPC-Ag 1.0 wt %) the reduced values of the compressive strength 4.0 ± 1.0 and 1.5 ± 1.0 MPa, respectively, were detected. Silver-ion release from CPC-Ag 0.6 wt % and CPC-Ag 1.0 wt % cements, measured by the Atomic Emission Spectroscopy, corresponds to the average values of 25 µg/L and 43 µg/L, respectively, rising a plateau after 15 days. The results of the antibacterial test proved the inhibitory effect towards pathogenic Escherichia coli for both CPC-Ag 0.6 wt % and CPC-Ag 1.0 wt % cements, better performances being observed for the cement with a higher Ag-content.

Micro-arc oxidation (MAO) is a versatile surface-modification method that promotes higher wear and corrosion resistance, osseointegration, and biological activity to titanium alloys’ surfaces. This study aimed to modify the surface of a recently developed metastable β Ti alloy, which exhibits more favorable mechanical properties for implant applications compared to some commercial Ti alloys, by incorporating Ag into the coatings to introduce a bactericidal function to the surface. The Ti-30Nb-5Mo alloy, with lower elastic modulus, was treated by the MAO method using electrolyte solutions containing calcium acetate, magnesium acetate, β-glycerol phosphate, and varied concentrations of silver nitrate (1.5 mM, 2.5 mM, and 3.5 mM). With an increase in the concentration of silver ions in the electrolyte, the galvanostatic period during the MAO process decreased from 1.7 s to 0.5 s. The Ca/P ratio increased from 0.72 up to 1.36. X-ray diffraction showed that the MAO coatings were formed by rutile and anatase TiO₂ main phases and calcium phosphates. X-ray photoelectron spectroscopy analysis detected the presence of amorphous Nb₂O₅, CaCO₃, and MgCO₃, and metallic and oxide forms of Ag. The increase in Ag in the electrolyte decreased the coating thickness (from 14.2 μm down to 10.0 μm), increased the contact angle (from 37.6° up to 57.4°), and slightly increased roughness (from 0.64 μm up to 0.79 μm). The maximum inhibition of Enterococcus faecalis, Pseudomonas aeruginosa, and Candida albicans strains growth was of 43%, 43%, and 61%, respectively. The Ag did not negatively affect the differentiation of adipose-tissue-derived mesenchymal stem cells. Therefore, the treatment of the surface of the innovative Ti-30Nb-5Mo alloy by the MAO method was effective in producing a noncytotoxic porous coating with bactericidal properties and improved osseointegration capabilities.

Due to their excellent mechanical properties and good biocompatibility, titanium (Ti) and its alloys are widely used as biomaterials. However, when implanted in the body, metallic materials may cause serious complications such as wear and infection, leading to patient discomfort and, in some cases, the need for revision surgery. Micro-arc oxidation (MAO) is a surface modification technique that offers a promising strategy to overcome these challenges. This study investigated the impact of the microstructure of Ti-25 Ta-xNb alloys (x = 10, 20, and 30 wt%) and the variation in applied voltage during the MAO process on the characteristics of the TiO₂ oxide coatings formed. The alloys were treated by MAO at 200, 250, and 300 V using a bioactive electrolyte containing Ca, P, Mg, and Ag. EDS, SEM, XRD, Raman spectroscopy, and adhesion tests performed characterization. Results indicated that Nb addition stabilized the β phase and anticipated the potentiostatic regime. Increasing the voltage supplied to the system provides greater energy, prolonging the galvanostatic regime and promoting the formation of larger and more uniform pores. The oxide coating thickness ranged from approximately 3 to 10 μm, with a tendency to decrease at higher voltages. The coatings exhibited low c, with anatase and rutile phases predominating, the applied voltage and Nb concentration influencing their relative proportions. Even in small amounts, all electrolyte elements (P, Mg, and Ag) were successfully incorporated into the coatings under all conditions. Raman and XRD analyses confirmed a decrease in anatase and an increase in rutile phases with increasing voltage and Nb content. Mechanical testing revealed good adhesion of the coatings in all samples, with the best results obtained at 200 V. The findings demonstrate that the developed coatings exhibit promising characteristics for future surface engineering strategies aimed at improving the performance of metallic biomaterials.