Publications

Orthopedic implants such as knee and hip implants are one of the most important types of medical devices. Currently, the surface of the most advanced implants consists of titanium or titanium-alloys with high porosity at the bone-contacting surface leading to superior mechanical properties, excellent biocompatibility, and the capability of inducing osseointegration. However, the increased surface area of porous titanium provides a nidus for bacteria colonization leading to implant-related infections, one of the main reasons for implant failure. Here, two readily applicable titanium-coatings based on hydrophilic carboxybetaine polymers that turn the surface stealth thereby preventing bacterial adhesion and colonization are developed. These coatings are biocompatible, do not affect cell functionality, exhibit great antifouling properties, and do not cause additional inflammation during the healing process. In this way, the coatings can prevent implant-related infections, while at the same time being completely innocuous to its biological environment. Thus, these coating strategies are a promising route to enhance the biocompatibility of orthopedic implants and have a high potential for clinical use, while being easy to implement in the implant manufacturing process.© 2023 The Authors. Macromolecular Bioscience published by Wiley-VCH GmbH.

JTD Keywords: bacteria repellency, biocompatibility, blood-plasma, brushes, stealth coatings, surface, titanium implants, Antifouling surfaces, Bacteria repellency, Biocompatibility, Brushes, Polymer brushes, Stealth coatings, Titanium implants

Previously, functional coatings on 3D-printed titanium implants were developed to improve their biointegration by separately incorporating Ga and Ag on the biomaterial surface. Now, a thermochemical treatment modification is proposed to study the effect of their simultaneous incorporation. Different concentrations of AgNO3 and Ga(NO3)3 are evaluated, and the obtained surfaces are completely characterized. Ion release, cytotoxicity, and bioactivity studies complement the characterization. The provided antibacterial effect of the surfaces is analyzed, and cell response is assessed by the study of SaOS-2 cell adhesion, proliferation, and differentiation. The Ti surface doping is confirmed by the formation of Ga-containing Ca titanates and nanoparticles of metallic Ag within the titanate coating. The surfaces generated with all combinations of AgNO3 and Ga(NO3)3 concentrations show bioactivity. The bacterial assay confirms a strong bactericidal impact achieved by the effect of both Ga and Ag present on the surface, especially for Pseudomonas aeruginosa, one of the main pathogens involved in orthopedic implant failures. SaOS-2 cells adhere and proliferate on the Ga/Ag-doped Ti surfaces, and the presence of gallium favors cell differentiation. The dual effect of both metallic agents doping the titanium surface provides bioactivity while protecting the biomaterial from the most frequent pathogens in implantology.

JTD Keywords: 3d-printing, agent, antibacterial activity, bioactive ti, biomaterials, coatings, competition, cu, gallium, glasses, ions, metal, porous structures, promote osseointegration, silver, titanium implants, In-vitro, Porous structures, Titanium implants

One of the major problems faced by metallic implants is the high probability of bacterial infections, with significant consequences for the patient. In this work, a thermochemical treatment is proposed to obtain silver-doped calcium titanate coatings on the Ti surface to improve the bioactivity of porous 3D-printed Ti structures and simultaneously provide them with antibacterial properties. A complete characterization of the new coating, the study of the ion release and the analysis of its cytotoxicity were carried out together with evaluation of the natural apatite forming in simulated body fluid (SBF). Moreover, the antibacterial properties of the coatings were assessed against Pseudomona aeruginosa and Escherichia coli as gram-negative and Staphylococcus aureus and Staphylococcus epidermidis as gram-positive bacterial strains. Ag ions were integrated into the Ca titanate layer and Ag nanoparticles were formed within the entire 3D Ti surface. Ca and Ag ions were released from both porous and solid samples into the Hanks' solution for 48 h. The treated surfaces showed no cytotoxicity and an apatite layer precipitated on the entire porous surface when the samples were immersed in SBF. The release of Ag from the surface had a strong antibacterial effect and prevented bacterial adhesion and proliferation on the surface. Moreover, the nanostructured topography of the coating resulted also in a reduction of bacterial adhesion and proliferation, even in absence of Ag. In conclusion, the cost-effective approach here reported provided protection against the most predominant bacterial colonizers to the Ti porous implants, while maintaining their bioactivity.

JTD Keywords: 3d-printing, alkaline, antibacterial activity, arthroplasty, bacterial adhesion, biomaterials, generation, ions, nanoparticles, osseointegration, silver, surface-layer, titanium implants, toxicity, 3d-printing, Antibacterial activity, Biomaterials, Porous structures, Silver, Ti metal, Titanium implants

Gallium (Ga) has been recently proposed as a novel therapeutic agent, since it promotes bone formation and exhibits antibacterial properties. This work focuses on the optimization of a thermochemical treatment that incorporates Ga ions by the addition of the body-friendly Ga nitrate approved by the Food and Drug Administration. The objective was to simultaneously provide the inner and the outer surfaces of porous‑titanium surfaces obtained by 3D-printing with bioactivity and antibacterial properties. The apatite-forming ability of the coating, as well as the antibacterial activity and SaOS-2 cell adhesion, proliferation, differentiation and mineralization were evaluated and compared with untreated Ti surfaces. The characterization of the surfaces revealed the presence of a Ga-containing calcium titanate layer, which was non cytotoxic and in simulated body fluid produced a homogeneous apatite coating well adhered to the substrate. The formation of this apatite layer was accelerated with increasing Ga amounts present on the surface, resulting also in an increase in thickness. An initial quick release of Ga ion promoted the antibacterial effect against gram positive strains, especially for Pseudomonas aeruginosa, one of the most frequent resistant pathogens in nosocomial infections. SaOS-2 cells adhered and proliferated on the Ga-doped Ti surfaces, its presence contributed to cell differentiation and to considerably increase the mineralization levels. Thus, the developed multifunctional coatings could provide bioactivity to the porous Ti implants while protecting them from the most frequent gram-negative pathogens.

JTD Keywords: 3D-printing, Antibacterial activity, Biomaterials, Gallium, Porous structures, Titanium implants