LAUSR

With the successful marriage between nanotechnology and oncology, various high‐Z element containing nanoparticles (NPs) are approved as radiosensitizers to overcome radiation resistance for enhanced radiotherapy (RT). Unfortunately, NPs themselves lack specificity to tumors. Due to the inherent tropism nature of malignant cells, mesenchymal stem cells (MSCs) emerge as cell‐mediated delivery vehicles for functional NPs to improve their therapeutic index. Herein, radiosensitive bismuth selenide (Bi2Se3) NPs‐laden adipose‐derived mesenchymal stromal cells (AD‐MSCs/Bi2Se3) are engineered for targeted RT of non‐small cell lung cancer (NSCLC). The results reveal that the optimized intracellular loading strategy hardly affects cell viability, specific surface markers, or migration capability of AD‐MSCs, and Bi2Se3 NPs can be efficiently transported from AD‐MSCs to tumor cells. In vivo biodistribution test shows that the Bi2Se3 NPs accumulation in tumor is increased 20 times via AD‐MSCs‐mediated delivery. Therefore, AD‐MSCs/Bi2Se3 administration synchronized with X‐ray irradiation controls the tumor progress well in orthotopic A549 tumor bearing mice. Considering that MSCs migrate better to irradiated tumor cells in comparison to nonirradiated ones and MSCs preferentially accumulate within lung tissues after systemic administration into accounts, the tumor‐tropic MSCs/NPs system is feasible and promising for targeted RT treatment of NSCLC.