Improved biocompatibility of Ti-based bulk metallic glasses by electrochemical formation of nanoporous oxide layers

Area of Science:

• Biomaterials Science
• Materials Science
• Surface Engineering

Background:

• Titanium-based bulk metallic glasses (BMGs) show promise for bone implants due to their mechanical properties.
• However, alloy design for high glass-forming ability can compromise biocompatibility, leading to corrosion and cytotoxic element release.
• Developing biocompatible Ti-BMGs requires addressing challenges like corrosion resistance and controlled ion release.

Purpose of the Study:

• To develop an electrochemical pseudo-dealloying treatment for Ti-BMG to enhance biocompatibility.
• To investigate the effects of this treatment on surface properties, corrosion resistance, and cellular response.
• To evaluate the potential of treated Ti-BMG as a bone implant material.

Main Methods:

• Electrochemical pseudo-dealloying treatment using 5 M HNO3 at 333 K on Ti47Cu38Zr7.5Fe2.5Sn2Si1Ag2 BMG.
• Anodic polarization and metal release studies (ICP-OES) in phosphate-buffered saline (PBS) and DMEM.
• In vitro studies using human bone marrow stromal cells (hBMSC) to assess cell morphology, metabolic activity, and osteogenic differentiation.

Main Results:

• The treatment generated nanoporous Ti/Zr oxide layers with near-surface Cu depletion.
• Reduced copper release rates and suppressed pitting corrosion were observed compared to non-treated surfaces.
• Treated surfaces exhibited enhanced wear resistance and maintained mechanical compressibility.
• In vitro studies showed increased hBMSC metabolic activity and TNAP activity on treated surfaces.
• Moderate formation of pro-inflammatory mediators suggests support for bone healing.

Conclusions:

• Electrochemical pseudo-dealloying is an effective method to improve the biocompatibility of Ti-BMGs.
• The nanoporous oxide surfaces enhance osseointegration potential by promoting cell activity and reducing adverse reactions.
• This treated Ti-BMG shows significant potential for bone implant applications, supporting the bone healing process.