Formation of Stable Amorphous Calcium Phosphate and Collagen Assemblies by a Versatile Spray‐Drying Approach

ABSTRACT Amorphous calcium phosphate (ACP) is proposed as a precursor phase in biologically controlled mineralization processes in both vertebrates and invertebrates. Therefore, there are increasing studies to understand the ACP stability in biomineralization events, as well as to use them in the development of hybrid scaffolds biomimetic of mineralized biological tissues. Its structural instability and uncontrolled crystallization under physiological conditions in vitro have limited its use for such different purposes, often requiring high concentrations of non‐physiological stabilizing agents. Here, we present a one‐pot, spray‐drying‐based, and scalable method for the rapid fabrication of either ACP or hybrid ACP‐collagen microparticles. The microparticles containing acetate, lacking counterions of ACP precursor salts such as Na + and Cl − , exhibit remarkable long‐term and thermal stability, and do not require the high concentrations of inorganic ions typically used for stabilization. In addition, from an applied perspective, they can form under physiological conditions biomimetic bone mineral but also, in the presence of collagen, extrudable 3D fibrillar bone‐like constructs. Finally, our work complements the understanding of ACP stabilization and its integration within organic scaffolds, both of which are essential for understanding biomineralization processes.