Amorphous calcium (ortho)phosphates

Area of Science:

• Biomaterials Science
• Materials Chemistry
• Biomineralization

Background:

• Amorphous calcium phosphates (ACPs) are glass-like calcium orthophosphate salts with no long-range atomic ordering.
• They are typically the initial solid phase in Ca(2+) and PO₄³⁻ solutions but can be produced via other methods.
• ACPs are thermodynamically unstable and tend to convert to crystalline phases like apatite.

Purpose of the Study:

• To review the occurrence, preparation, composition, structure, properties, and biomedical applications of amorphous calcium phosphates.
• To highlight the biological relevance and potential of ACPs in biomineralization and bone tissue engineering.

Main Methods:

• Literature review and synthesis of existing knowledge on amorphous calcium phosphates.
• Systematization of references to aid reader navigation.

Main Results:

• Wet-chemically prepared ACPs exhibit a consistent composition, suggesting a local structure like the Posner cluster.
• ACPs play a crucial role as intermediates in skeletal calcification and matrix vesicle biomineralization.
• ACPs demonstrate excellent biocompatibility and bioresorbability, making them suitable for artificial bone grafts.

Conclusions:

• Amorphous calcium phosphates are key intermediates in biomineralization processes.
• Their properties make them highly promising for developing advanced bone graft materials.
• Further research into ACPs can advance both fundamental understanding and clinical applications.