Bioinspired Dormant-ATP-Stabilized Biomineral Amorphous Nanoparticles and Saliva-Activated Rapid Mineralization...

The high stability of storage and high mineralization efficiency are pivotal for the restoration of acid-etched dental enamel, yet these demands are mutually exclusive and difficult to be met. Herein, we propose a bioinspired "dormancy-to-activation" mineralization strategy by synthesizing "dormant" adenosine 5'-triphosphate (ATP)-stabilized amorphous calcium phosphate (ACP) nanoparticles as the precursor that can be activated and accelerated by saliva for rapid crystallization to form hierarchically ordered crystalline hydroxyapatite nanorods (mineralization). To realize this goal, we have designed and constructed a bioinspired dormant-ATP-stabilized ACP nanoparticle system with high stability and controllable mineralization ability using ATP biomolecules as the stabilizer. The ACP-ATP nanoparticles can maintain the dormancy for mineralization in vitro, which can stabilize the amorphous structure of ACP nanoparticles for 25 days in water. In the oral environment, the alkaline phosphatase (ALP) in saliva acts as a biological signal to activate and accelerate the mineralization of ACP-ATP amorphous nanoparticles. More importantly, the coating of ACP-ATP amorphous nanoparticles on the acid-etched dental enamel can effectively restore the hierarchically ordered structure, recover mechanical properties, and replicate fracture-resistance behaviors of natural dental enamel.