A Drug-Mineralized Hydrogel Orchestrated by Spontaneous Dynamic Mineralization

Fabrication of mineralized materials through the nature-mimicking dynamic biomineralization process has attracted great interest but remains a huge challenge till now. Here, a drug-mineralized hydrogel (DMH) with spontaneous dynamic mineralization behaviors is reported, which highly mimics the dynamic mineralization process of natural tissues. The hydrogel is facilely fabricated via directly mixing sodium hyaluronate (HA) with alendronate sodium (ADA) and CaCl 2 in deionized water. The resultant hydrogel possesses a white-to-semi-transparent transition and a soft-to-hard transition during incubation at 37 °C. Mechanism studies reveal that the spontaneous dynamic change of the hydrogel is ascribed to the HA-regulated dynamic mineralization of ADA/Ca 2+ complexes, where amorphous ADA/Ca 2+ complexes will gradually transform into mineral crystals with the prolongation of incubation time. Owing to the dynamic transformation process, the DMH shows excellent injectability and moldability at the initial stage. More importantly, the DMH exhibits a sustained release behavior of ADA in vitro, superior adhesiveness with bone, biodegradability, and good biocompatibility. As a result, the developed DMH demonstrates promising uses for accelerating bone repair in a rat cranial defect model. Overall, the research provides a general strategy to prepare drug-mineralized hydrogels with spontaneous dynamic mineralization behaviors, which may find potential uses in various biomedical fields.