Tumor Eradication by Boron Neutron Capture Therapy with 10B‐enriched Hexagonal Boron Nitride Nanoparticles Grafted with Poly(Glycerol)

Abstract Boron neutron capture therapy (BNCT) has emerged as a treatment modality with high precision and efficacy of intractable tumors. At the core of effective tumor BNCT are 10 B carriers with facile preparation as well as advantageous pharmacokinetic and therapeutic profiles. Herein, the design and preparation of sub‐10 nm 10 B‐enriched hexagonal boron nitride nanoparticles grafted with poly(glycerol) (h‐ 10 BN‐PG), and their application to cancer treatment by BNCT are reported. By virtue of their small particle size and outstanding stealth property, h‐ 10 BN‐PG nanoparticles accumulate efficiently in murine CT26 colon tumors with a high intratumor 10 B concentration of 8.8%ID g −1 or 102.1 µg g −1 at 12 h post‐injection. Moreover, h‐ 10 BN‐PG nanoparticles penetrate into the inside of the tumor parenchyma and then are taken up by the tumor cells. BNCT comprising a single bolus injection of h‐ 10 BN‐PG nanoparticles and subsequent one‐time neutron irradiation results in significant shrinkage of subcutaneous CT26 tumors. h‐ 10 BN‐PG‐mediated BNCT not only causes direct DNA damage to the tumor cells, but also triggers pronounced inflammatory immune response in the tumor tissues, which contributes to long‐lasting tumor suppression after the neutron irradiation. Thus, the h‐ 10 BN‐PG nanoparticles are promising BNCT agents to eradicate tumor through highly efficient 10 B accumulation.