Crystallization and sintering of borosilicate bioactive glasses for application in tissue engineering

Area of Science:

• Biomaterials Science
• Materials Chemistry
• Tissue Engineering

Background:

• Silicate bioactive glasses readily crystallize during scaffold processing, hindering reaction rates and ion release.
• Non-congruent dissolution of silicate glasses leads to long-term persistence in vivo.
• There is a need for bioactive materials with improved dissolution and higher conversion rates.

Purpose of the Study:

• To investigate the effect of substituting silicon dioxide (SiO2) with boron (B2O3) in FDA-approved S53P4 glass.
• To evaluate the crystallization, sintering, and bioactivity of novel boron-containing bioactive glasses.
• To develop amorphous bioactive glass scaffolds with controlled porosity and mechanical properties.

Main Methods:

• Differential thermal analysis was used to study crystallization and sintering behavior.
• Boron was incorporated into S53P4 glass by replacing SiO2 at varying percentages (25%, 50%, 75%).
• Heat sintering was employed to fabricate porous scaffolds, and their porosity, pore size, and compressive strength were analyzed.

Main Results:

• Boron incorporation reduced surface crystallization, with precipitation dependent on B2O3 content.
• Lower crystallization rates were observed with increased B2O3 substitution.
• Porous scaffolds with 10-60% porosity and 1-35 MPa compressive strength were successfully fabricated.
• Scaffolds remained amorphous and maintained rapid hydroxycarbonate apatite precipitation.

Conclusions:

• Replacing SiO2 with B2O3 in S53P4 glass yields amorphous bioactive scaffolds with controlled properties.
• These amorphous scaffolds exhibit faster degradation and reaction rates compared to crystallized bioactive glasses.
• The developed materials show promise for tissue engineering applications requiring predictable scaffold behavior.