ZnO capped flower-like porous carbon-Fe3O4 composite as carrier for bi-triggered drug delivery

Abstract In this work, ZnO capped flower-like porous carbon-Fe3O4 composite (FPCS-Fe3O4-ZnO) was constructed as a carrier for pH and microwave bi-triggered drug delivery. In the composite, the FPCS achieves high-efficiency drug loading, the Fe3O4 acts as magnetic targeting agent and microwave absorption enhancer, and the ZnO nanoparticle as a sealing agent in response to pH stimulation. The carrier exhibited a flower-mesoporous sphere of 270 nm, a specific surface area of 101 m2/g, a saturation magnetization of 14.08 emu/g, as well as good microwave thermal conversion properties (The temperature was raised from 25 °C to 60 °C only 24 s). Simultaneously, the carrier achieved an efficient drug loading with a drug loading rate of 99.1%. During the drug release experiments, obvious pH-dependent release behavior was observed, the drug release rate at 12 h was 8.2%, 19.0%, and 56.3% at pH 7.4, 5.0 and 3.0 respectively. Moreover the drug release rate increased from 8.2% to 39.9% after microwave stimulation at pH 7.4. In addition, cytotoxicity tests indicate that the carrier has good biocompatibility. Thus, this multifunctional pH and microwave bi-triggered carrier was expected to be further applied to drug delivery system(DDS).