a new

implantable hierarchical-structured ultrafine fiber device is developed via a

microfluidic-electrospinning technology for localized codelivery of doxorubicin

(DOX) and apatinib (AP). An extremely high encapsulation efficiency of

≈99% for the dual drugs is achieved through this strategy. The release of the

loaded dual drugs can be controlled in a programmable release model with

a rapid release of the micelles, while AP is slowly released. The sustained

release of AP can continuously inhibit the P-gp drug pump of MDR tumor

cells, increasing the intracellular DOX accumulation. The in vivo DOX biodistribution

displays that the DOX accumulation in the tumor tissues achieves

17.82% after implanting the fiber device for 72 h, which is 6.36-fold higher

than that of the intravenously injected DOX. Importantly, the fiber device

shows an excellent antitumor effect on MDR tumor-bearing mice with low