Prof. XING Gengmei's group from the Institute of High Energy Physics of the Chinese Academy of Sciences recently made progress in the development of nano-drugs for the treatment of malignant glioma. The study was published in Advanced Functional Materials.

Boron neutron capture therapy (BNCT) is a noninvasive radiation therapy for treating tumors. Due to the unique physiological and anatomical features of the brain, very few drugs can successfully access brain tissue, and the relatively poor curative effects of surgery contribute to the poor prognosis and low survival rate of brain glioma. Due to the advantages of neutron radiation, however, BNCT is expected to improve the treatment of cancers considered incurable, such as brain glioma.

BNCT works through a two-step process. First, drugs containing the nonradioactive isotope boron-10 (¹⁰B)—which has a strong capacity for capturing thermal neutrons—are delivered to the tumor tissue. Second, a precise dose of thermal electrons is directed at the tumor. Boron-10 then captures the neutrons and releases alpha particles into the surrounding tumor, killing the tissue.

To improve the curative effect of BNCT on brain glioma, the researchers designed and constructed novel ¹⁰B boron-containing carbon dots (BCDs) that they then encapsulated in exosomes to form ~ 100 nm BCD-Exos. The BCD-Exos proved to have high tumor selectivity, a high capacity for crossing the blood brain barrier, and good in vivo tumor site accumulation.

BNCT with BCD-Exos prolonged the survival rate of the experimental mice to 100% at day 30 (i.e., the end of the experiment). The excellent curative effect of BNCT with BCD-Exos in treating brain glioma in vivo was achieved by adjusting the distribution of BCD-Exos in the cancer cells and precisely matching boron accumulation with neutron exposure using fluorescent imaging of the BCD-Exos.