LAUSR

Novel boron‐containing carbon dots (BCDs) are designed and prepared for boron neutron capture therapy (BNCT) with superior water solubility and excellent optical property for tracking 10B in vitro and in vivo. Encapsulation of BCDs using exosomes (Exos) from macrophages yields BCD–Exos of ≈100 nm. Fluorescent imaging shows that the BCD–Exos are internalized and distributed around the nuclei of U‐87‐MG glioma cells. BCD–Exos are also verified to cross the blood–brain barrier and significant accumulation in tumor tissue of the orthotopic U‐87‐MG glioma tumor‐bearing mice model 4 h after administration. Using inductively coupled plasma mass spectrometry (ICP‐MS), it is detected that 10B in tumor tissue is 107.07 ± 1.58 ppm, and T/N ratios are enhanced from 2.03 ± 0.08 of boron phenylalanine (BPA) to 5.28 ± 0.29 of the BCD–Exos. In BNCT, the neutron radiation dose is 8.40 ± 0.12 Gy when a 500 mg kg−1 10B dosage is given. Finally, there is a prominent BNCT effect of the BCD–Exos‐treated brain glioma in the mice model, and the survival ratio is 100% at the end of the experiment. The excellent curative effect of BNCT using BCD–Exos to brain glioma is achieved through adjusted biodistribution of boron in the cancer cell, enhanced T/N ratios, and the precise match between boron and neutron exposure in the site of the tumor in vivo with fluorescence imaging of BCD–Exos.