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The excessive reactive oxygen species (ROS) is a hallmark associated with the initiation and progression of inflammatory bowel disease (IBD), which execrably form a vicious cycle of ROS and inflammation to continually promote disease progression. Here, the gold nanoparticles-embedded ceria nanoparticles (Au/CeO2) with enhanced antioxidant activities are designed to block this cycle reaction for treating IBD by scavenging overproduced ROS. The Au/CeO2 with core-shell and porous structure exhibits significantly higher enzymatic catalytic activities compared with commercial ceria nanoparticles, likely due to the effective exposure of catalytic sites, higher content of Ce (III) and oxygen vacancy, and accelerated reduction from Ce (IV) to Ce (III). Being coated with negatively-charged hyaluronic acid, the Au/CeO2@HA facilitates accumulation in inflamed colon tissues via oral administration, reduces pro-inflammatory cytokines, and effectively alleviates colon injury in colitis mice. Overall, the Au/CeO2@HA with good biocompatibility is a promising nano-therapeutic for treating IBD.

Chemotherapy is one of the major approaches for the treatment of metastatic lung cancer. However, systemic chemotherapy is limited by poor therapeutic efficiency and severe toxic side effects, due to the extremely low delivery efficacy and non-specificity of anticancer drugs. Herein, we report a sericin microparticles enveloped with metal-organic networks as a pulmonary delivery system for treating lung metastasis of breast cancer in an animal model. The sericin microparticles (SMPs) were prepared using water in oil (w/o) emulsification method. After doxorubicin (DOX) loading, tannic acid (TA)/ferric irons (Fe3+) based metal organic networks (MON) were coated on the particles to obtain DOX-loaded microparticles (DOX@SMPs-MON). The SMPs-MON with good biocompatibility could effectively encapsulate DOX and sustainably unload cargos in a pH-dependent manner. The DOX-loaded microparticles could be uptaken by 4T1 cells, and effectively kill the cancer cells. In vivo, DOX@SMPs-MON was deposited in the lungs and remained for over 5 days after pulmonary administration. In contrast to conventional DOX treatment that did not show significantly inhibitory effects on lung metastatic tumor, DOX@SMPs-MON markedly decreased the number and size of metastatic nodules in lungs, and the lung weight and appearance were similar to those of healthy mice. In summary, the sericin microparticles with MON wrapping might be a promising pulmonary delivery system for treating lung metastatic cancer.