Surface functional group dependent apatite formation on bacterial cellulose microfibrils network in a simulated body...

Area of Science:

• Biomaterials Science
• Biomineralization
• Materials Chemistry

Background:

• Bacterial cellulose (BC) is a biopolymer with potential biomedical applications.
• Understanding apatite formation on BC is crucial for bone tissue engineering.
• Simulated body fluid (SBF) mimics physiological conditions for in vitro biomineralization studies.

Purpose of the Study:

• To investigate the apatite-forming ability of bacterial cellulose (BC).
• To explore the effect of surface modifications on apatite nucleation and growth.
• To elucidate the mechanism of apatite formation on BC in simulated body fluid (SBF).

Main Methods:

• Soaking BC specimens in 1.5 SBF at 37°C and pH 7.4.
• Surface modification of BC using TEMPO-mediated oxidation.
• Ion exchange treatment with calcium chloride solution.
• Analysis using ATR-FTIR, ICP-AES, SEM, FE-SEM, and TEM.

Main Results:

• Calcium-deficient carbonated apatite nucleated on BC microfibrils, forming through octacalcium phosphate (OCP) or OCP-like phases.
• Apatite deposits formed globules of varying sizes (<1 µm to 3 µm) depending on the BC substrate.
• TEMPO-mediated oxidation enhanced apatite nucleation rate by introducing carboxyl groups.
• Calcium chloride ion exchange post-TEMPO oxidation yielded the highest deposit weight and smallest apatite globules.

Conclusions:

• BC substrates influence the rate and morphology of apatite mineralization.
• Surface functionalization strategies, particularly TEMPO-oxidation and Ca2+ treatment, significantly enhance apatite formation on BC.
• The findings provide insights into designing BC-based materials for bone regeneration applications.