Preparation and characterization of mesoporous bioactive glass from agricultural waste rice husk for targeted anticancer drug delivery

Mesoporous bioactive glass (MBG) possesses excellent biocompatibility and an important material used for bone regeneration and drug delivery. The aim of this study is to synthesize MBG from low-cost agricultural waste rice husk (rMBG) using a sol-gel process. We show that rMBG has typical characteristics of the well-ordered hexagonal mesostructure of MBG and can be grafted with folic acid (FA) and then loaded with anticancer drugs for targeting cancer cells. By loading rMBG-FA with camptothecin (CPT, a water-insoluble anticancer drug) we formed rMBG-FA/CPT, which killed cancer cells by being selectively and efficiently taken in via the cells' FA receptors (FRs). We found that rMBG-FA/CPT showed a higher cytotoxicity to FR-overexpressed HeLa cells than to FR-deficient L929 cells. Our results indicate that low-cost rMBG offers a potentially practical medical application that can replace highly valuable MBG as well as reduce environmental pollution caused by agricultural waste.