Attapulgite microspheres coated with poly(lactic acid-glycolic acid) nanoparticles form satellite structure to enhance doxorubicin delivery in bone cancer therapy

The micro-nano structure of drug delivery systems, which realize the release of the drug in stages, represent a promising therapeutic approach for tumor chemotherapy. In this study, we developed a drug delivery system in which nano-PLGA was coated on the surface of attapulgite microspheres (ATT-MS) loaded with doxorubicin hydrochloride (DOX). Nano-PLGA surrounding ATT-MS formed a satellite structure, which improved the drug release rate by blocking the drug release channels with the nano-PLGA. The drug delivery system achieves a high DOX encapsulation efficiency (98 %) and enables passive, tumor-selective drug release. The zeta potential and drug release curve showed that DOX in this drug delivery system is more readily released in the tumor microenvironment. The fluorescence imaging and Western blot analysis showed that the drug delivery system has the potential to improve tumor resistance. Moreover, the in vivo experiment showed that the system not only maintained the anticancer activity but also reduced the organ damage. In conclusion, this micro-nano structure of the drug delivery system may provide a novel approach to effectively deliver DOX to the tumor and reduce systemic toxicity.