On-site smart biomimetic mineralization of starch-templated CaP prenucleation clusters triggered by α-amylase

With the attention of biomineralization, calcium phosphate precursor phases regulated by different organic templates are synthesized and used as mineral sources for biomimetic mineralization. However, most of the organic templates have limited ability to stabilize calcium and phosphorus ions, or the selected templates have poor biocompatibility and irremovability, which make them difficult to co-exist in long-term stability and crystal transformation, and to achieve convenient and harmless clinical application. Herein, we propose a calcium phosphate prenucleation clusters (CaP-PNCs)/starch complex, which includes uniform-sized, separate, and homogeneously distributed amorphous calcium phosphate nanoclusters of about 1 nm. By means of freeze-drying and redissolution, the CaP-PNCs/starch complex can be converted between liquid and spongy solid without changing their morphology and amorphous phase, and the freeze-dried CaP-PNCs/starch complex can be stored at room temperature for at least 5 months. Imitating the mechanism of protein-protease controlled biomineralization in organisms, the CaP-PNCs/starch complex is mixed with α-amylase during application. Starch templates are removed by enzymolysis and CaP-PNCs can be released, thus triggering on-site biomimetic mineralization with enamel-like structures to repair tooth tissue defects (including enamel and dentin). CaP-PNCs/starch complex provides a smart mineral source supply for biomimetic mineralization and a new pathway for the design of biomimetic materials.