Injectable Silk–Vaterite Composite Hydrogels with Tunable Sustained Drug Release Capacity

Improving the efficiency of chemotherapy remains a key challenge in drug delivery. Many drug carriers have been designed to achieve multifunctional factors as part of their performance, including controlled release, dispersibility in aqueous environments, and targeting to cancer sites. However, it is difficult to optimize multiple properties simultaneously for a single carrier system. Here, synergistic carriers composed of vaterite microspheres and silk nanofiber hydrogels were developed to improve the dispersibility of vaterite spheres and the control of drug delivery without compromising the injectability or sensitivity to pH. The vaterite microspheres were dispersed homogeneously and remained stable in the silk nanofiber hydrogels. Doxorubicin (DOX) was effectively loaded on the vaterite spheres and silk nanofibers, forming synergistic silk-vaterite hydrogel delivery systems. The sustained delivery of DOX was tuned and controlled by vaterite stability and the DOX content loaded on the spheres and nanofibers. The cytotoxicity was regulated via the controlled delivery of DOX, suggesting the possibility of optimizing chemotherapeutic strategies. These silk-vaterite delivery hydrogels suggest a useful strategy for designing novel delivery systems for improved delivery and therapeutic benefits.