Development of bioactive and antimicrobial nano-topography over selective laser melted Ti6Al4V implant and its in-vitro corrosion behavior.

Additive manufacturing (AM) or 3D printing of bone defect models is gaining much attention in the biomedical field as it could significantly facilitate the development of customized implants with a high degree of dimensional accuracy. Due to their satisfactory biocompatibility and minimal stress shielding effect, Ti6Al4V (Ti64) alloys are increasingly preferred in the development of such implants. However, their poor osseointegration abilities and lack of antibacterial properties often cause implant loosening and microbial infections, leading to implant failure. To address these drawbacks, we propose in this work a simple surface modification approach of customized Ti64 alloys (3D printed Ti6Al4V) that enables the formation of porous calcium titanate (CT) over their surface as well as the incorporation of silver nanoparticles (AgNPs) into the thus formed porous network. The successful CT formation with the incorporation of AgNPs throughout the 3D printed Ti64 surface and their influence in changing the morphological and mechanical behaviour were studied by Raman spectroscopy, SEM, AFM, Contact angle measurement, XPS, HR-TEM and nano-indentation. Antibacterial studies using Staphylococcus aureus and Escherichia coli, and in-vitro cell studies using MG-63 cell lines showed that surface modified samples resulting from the proposed method exhibit satisfactory antimicrobial property and are highly biocompatible. The obtained surface modified samples also showed a significant improvement in corrosion resistance as compared to unmodified 3D printed Ti64 alloys. The improvement in corrosion resistance was revealed by electrochemical impedance Spectroscopy (EIS). Obtained results emphasis that thus surface modified 3D printed Ti64 alloys are promising candidates for hard tissue implant applications.

Cerium Ion-Incorporated Titanium Metal Implants of Enhanced Bioactivity for Biomedical Applications.

The enhancement in the performance of metallic bone implants based on commercially pure titanium (CP-Ti) by incorporation of cerium (Ce) ions onto the surface was evaluated. The incorporation of Ce ions onto the CP-Ti surface was carried out by a simple two-step chemical treatment method, where an initial NaOH treatment and then a subsequent treatment with different molar concentrations of ceric nitrate solution followed by heat treatment at 600 °C were carried out. The modified surfaces were observed using field emission scanning electron microscopy (FE-SEM), scanning electron microscopy-energy dispersive X-ray analysis (SEM-EDX), X-ray photoelectron spectroscopy (XPS), the laser Raman spectroscopic technique, high-resolution transmission electron microscopy (HR-TEM), and atomic force microscopy (AFM). The formation of a nanonetwork structure by the initial NaOH treatment and the replacement of Na ions with Ce ions along with different phases of TiO2 was evident from the surface characterization results. The transition of rutile TiO2 to anatase TiO2 in the modified surface is evident from the Raman spectra with respect to the treatment of higher to lower concentrations of ceric nitrate solution. The presence of two different oxidation states of Ce (Ce3+ and Ce4+) and improvement in the surface wettability were also distinct in the modified samples. Thus, the incorporated Ce ions over the nanostructured titania network showed low cytotoxicity, good cell adhesion, and enhanced extracellular mineralization on MG-63 cells with better protein adsorption in BSA medium. Taken together, the thus-improved nanostructured surface morphology with the anatase TiO2 phase and distinct extracellular mineralization in the Ce-incorporated Ti metal with good biocompatibility make it a promising candidate for bone implant applications.