Magnesium Phosphate Cement as Mineral Bone Adhesive

Area of Science:

• Biomaterials Science
• Orthopedic Research
• Materials Chemistry

Background:

• Mineral bone cements, including calcium phosphate cements (CPC), were initially designed as bone void fillers, not bone adhesives.
• CPC are often unsuitable for bone bonding, especially in moist environments.
• Magnesium phosphate cements (MPC) present a potential alternative for bone adhesion applications.

Purpose of the Study:

• To evaluate the ex vivo bone-bonding capabilities of magnesium phosphate cements (MPC).
• To investigate the influence of phytic acid concentration and powder-to-liquid ratio (PLR) on MPC adhesion.
• To explore the potential of MPC as bone adhesives.

Main Methods:

• Synthesized MPC from farringtonite and varying concentrations of phytic acid (inositol hexaphosphate, IP6).
• Cement setting was achieved via chelation between Mg2+ ions and IP6.
• Assessed ex vivo shear strength on bovine cortical bone substrates under aqueous conditions.
• Utilized scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX) analysis to examine failure modes and cement residues.

Main Results:

• MPC formulations with 25% IP6 and a PLR of 2.0 g/mL achieved shear strengths of 0.81 ± 0.12 MPa on bone after 7 days in aqueous conditions.
• Failure analysis indicated a mixed adhesive-cohesive mode with residual cement on the bone surface.
• SEM and EDX confirmed the presence of cement residues, supporting adhesive bonding.

Conclusions:

• Optimized magnesium phosphate cements exhibit promising ex vivo bone adhesion properties.
• These MPC formulations demonstrate suitability for applications requiring bone bonding, even in challenging aqueous environments.
• The findings suggest a potential expansion of mineral bone cement applications into the field of bone adhesives.