Shear-mediated crystallization from amorphous calcium phosphate to bone apatite.

Area of Science:

• Biomaterials Science
• Biomineralization
• Cell Biology

Background:

• Bone apatite formation is crucial for skeletal integrity.
• Understanding biomineralization mechanisms is key for bone regeneration.
• Fluid shear stress (FSS) is a physiological factor in bone remodeling.

Purpose of the Study:

• To investigate the effect of fluid shear stress (FSS) on the conversion of amorphous calcium phosphate (ACP) to bone apatite.
• To determine the optimal FSS for enhanced apatite formation and bioactivity.

Main Methods:

• Amorphous calcium phosphate (ACP) synthesized via wet-chemistry.
• ACP exposed to varying FSS levels (0.5–2.0 Pa).
• Characterization using TEM, XRD, ICP-MS, and bioactivity assays.

Main Results:

• Low FSS (≤1.0 Pa) accelerated ACP crystallization into well-organized calcium-deficient hydroxyapatite (CDHA).
• High FSS (>1.0 Pa) resulted in poor CDHA morphology and structural damage.
• CDHA formed under 1.0 Pa FSS exhibited superior biocompatibility with pre-osteoblast cells.

Conclusions:

• FSS significantly modulates ACP to CDHA conversion.
• Optimal FSS (around 1.0 Pa) promotes the formation of bioactive bone apatite.
• Findings provide insights into natural bone apatite deposition mechanisms.