Ductile silica/methacrylate hybrids for bone regeneration

Area of Science:

• Biomaterials science
• Materials chemistry
• Tissue engineering

Background:

• Bioglass® is a bone-bonding synthetic material but lacks toughness.
• Ideal synthetic bone grafts require both bone bonding and mechanical resilience.
• Existing materials often present a trade-off between mechanical properties and bioactivity.

Purpose of the Study:

• To investigate polymethacrylate-silica (class II hybrid) materials as a new generation of bone scaffold.
• To enhance the mechanical properties, particularly toughness, of synthetic bone graft materials.
• To evaluate the bioactivity and cytocompatibility of these novel hybrid materials.

Main Methods:

• Synthesis of poly(3-(methoxysilyl)propyl methacrylate) (pTMSPMA)/silica hybrids using tetraethyl orthosilicate (TEOS) with varying inorganic to organic ratios (Ih).
• Characterization of hybrid porosity, pore size, and surface area.
• Mechanical testing including strain to failure and modulus of toughness (UT).
• Assessment of apatite forming ability in simulated body fluid (SBF) and in vitro cytotoxicity using MC3T3-E1 cells.

Main Results:

• The hybrids exhibited nanoporosity with a modal pore diameter of 1 nm.
• At Ih = 50%, increasing pTMSPMA molecular weight enhanced strain to failure up to 14.2% and modulus of toughness to 2.64 GPa.
• pTMSPMA/SiO2 hybrids nucleated bone-like mineral in SBF, unlike pure silica sol-gel glass.
• Improved cell attachment and no adverse cytotoxicity were observed for the hybrids.

Conclusions:

• pTMSPMA/SiO2 hybrids demonstrate significantly improved toughness compared to pure glass.
• The hybrids exhibit enhanced apatite forming ability, crucial for bone regeneration.
• These materials overcome the brittleness of inorganic bone grafts while maintaining cell compatibility, showing potential for hard tissue regeneration.