Biomineralization of Stable and Monodisperse Vaterite Microspheres Using Silk Nanoparticles
2015
Liu, Lijie | Zhang, Xiuli | Liu, Xi | Liu, Jing | Lu, Guozhong | Kaplan, David L. | Zhu, Hesun | Lu, Qiang
The influence of silk fibroin (SF) on calcium carbonate (CaCO₃) biomineralization has been investigated; however, the formation of small, uniform SF-regulated vaterite microspheres has not been reported. In this work, spherical CaCO₃ was synthesized via coprecipitation in the presence of SF. SF nanostructures were first tuned by self-assembly at 60 °C to provide better control of the nucleation of CaCO₃. Subsequently, monodisperse vaterite microspheres about 1.1 μm were generated by controlling aggregation and growth of CaCO₃ under appropriate concentrations of SF and Ca ions. In contrast to unstable vaterite, the microspheres generated in the present study have sufficient stability in aqueous solution for at least 8 days without transformation into calcite, due to the electrostatic interactions between the Ca ions and the preassembled SF nanostructures. The microspheres as drug carriers of doxorubicin (DOX) were assessed and found to have good encapsulation efficiency, sustained drug release without burst release, and pH sensitivity. These new SF/CaCO₃ hybrids may provide new options for various biomedical applications.
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