Versatile Biodegradable Poly(acrylic acid)-Based Hydrogels Infiltrated in Porous Titanium Implants to Improve the...

Area of Science:

• Biomaterials Science
• Orthopedic Engineering
• Polymer Chemistry

Background:

• High Young's modulus mismatch between titanium implants and cortical bone can lead to stress shielding and implant failure.
• Bacterial adhesion and proliferation on implant surfaces are significant challenges, causing infections and hindering osseointegration.

Purpose of the Study:

• To develop a synergistic approach to improve implant performance by addressing mechanical mismatch and bacterial challenges.
• To fabricate porous titanium substrates and biodegradable poly(acrylic acid)-based hydrogels.
• To evaluate the combined efficacy of these strategies for enhanced osseointegration and reduced bacterial adhesion.

Main Methods:

• Fabrication of porous commercially pure titanium (Ti) substrates with varying porosities and pore sizes using space-holder techniques.
• Synthesis of biodegradable poly(acrylic acid)-based hydrogels using a novel diacrylate cross-linker with a reduction-sensitive disulfide bond.
• Characterization of fabricated materials and evaluation of the combined hydrogel-infiltrated porous Ti substrates.

Main Results:

• Porous Ti substrates demonstrated improved tribomechanical behavior.
• Biodegradable hydrogels with varying cross-linker concentrations (1%, 2%, 4%) were successfully synthesized.
• The combination of 4% cross-linked poly(acrylic acid)-based hydrogel infiltrated in 30 vol % porosity Ti substrates (100-200 μm pore size) showed outstanding performance.

Conclusions:

• The synergistic approach effectively reduces the Young's modulus mismatch between Ti implants and bone.
• The biodegradable hydrogel coating inhibits bacterial adhesion and proliferation.
• The optimized combination of porous Ti and hydrogel coating represents a promising strategy for next-generation orthopedic implants.