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 ¹⁰B carriers with facile preparation as well as advantageous pharmacokinetic and therapeutic profiles. Herein, the design and preparation of sub‐10 nm ¹⁰B‐enriched hexagonal boron nitride nanoparticles grafted with poly(glycerol) (h‐¹⁰BN‐PG), and their application to cancer treatment by BNCT are reported. By virtue of their small particle size and outstanding stealth property, h‐¹⁰BN‐PG nanoparticles accumulate efficiently in murine CT26 colon tumors with a high intratumor ¹⁰B concentration of 8.8%ID g⁻¹ or 102.1 µg g⁻¹ at 12 h post‐injection. Moreover, h‐¹⁰BN‐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‐¹⁰BN‐PG nanoparticles and subsequent one‐time neutron irradiation results in significant shrinkage of subcutaneous CT26 tumors. h‐¹⁰BN‐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‐¹⁰BN‐PG nanoparticles are promising BNCT agents to eradicate tumor through highly efficient ¹⁰B accumulation.