Micropatterned Silica Films with Nanohydroxyapatite for Y-TZP Implants

Area of Science:

• Biomaterials Science
• Materials Engineering
• Nanotechnology

Background:

• Yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) is a common dental and orthopedic material.
• Developing bioactive coatings for Y-TZP can improve osseointegration and cellular response.
• Micropatterned silica thin films (MSTFs) offer a platform for controlled surface topography and bioactivity.

Purpose of the Study:

• To create MSTFs incorporating nanohydroxyapatite (nano-HA) microaggregates with exposed surfaces for direct cell interaction.
• To assess the impact of MSTFs (with or without nano-HA) on the mechanical strength (characteristic strength σ₀ and Weibull modulus m) of Y-TZP.
• To evaluate the in vitro cellular response (morphology, orientation, proliferation) of MG63 cells on these coated Y-TZP surfaces.

Main Methods:

• Sol-gel process and soft lithography were employed to fabricate MSTFs on Y-TZP specimens.
• Three groups were tested: Y-TZP, Y-TZP + MSTF, and Y-TZP + MSTF + nano-HA.
• Surface characterization used scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS).
• Mechanical properties were evaluated via 4-point flexural strength testing and analyzed using Weibull statistics.
• In vitro biological evaluation involved culturing MG63 cells on the different surfaces.

Main Results:

• Successful fabrication of MSTFs with partially exposed nano-HA microaggregates on Y-TZP.
• No statistically significant differences were observed in the characteristic strength (σ₀) or Weibull modulus (m) of Y-TZP with or without the developed films.
• MG63 cells cultured on the films exhibited elongated morphology and aligned along the micropatterned lines.
• The MSTF + nano-HA group demonstrated significantly higher MG63 cell metabolic activity and proliferation at day 7 compared to uncoated Y-TZP.

Conclusions:

• The developed MSTFs with exposed nano-HA are effective in promoting MG63 cell activity and proliferation.
• The MSTFs do not negatively impact the structural reliability of Y-TZP, as confirmed by mechanical testing and Weibull analysis.
• The combination of micropatterning and nano-HA creates a promising bioactive surface for enhanced cellular response on Y-TZP materials.