Polyethylene moderator optimized for increasing thermal neutron flux in the NASBEE accelerator-based neutron field

Enhancing Cancer Therapy: Boron-Rich Polyboronate Ester Micelles for Synergistic Boron Neutron Capture Therapy and PD-1/PD-L1 Checkpoint Blockade

Malignant cancers, known for their pronounced heterogeneity, pose substantial challenges to monotherapeutic strategies and contribute to the risk of metastasis. Addressing this, our study explores the synergistic potential of combining boron neutron capture therapy (BNCT) with immune checkpoint blockade to enhance cancer treatment efficacy. We synthesized boron-rich block copolymer micelles as a novel boron drug for BNCT. Characterization was conducted using nuclear magnetic resonance, gel-permeation chromatography, transmission electron microscopy, and dynamic light scattering. These micelles, with an optimal size of 91.3 nm and a polydispersity index of 0.18, are suitable for drug delivery applications. In vitro assessments on B16-F10 melanoma cells showed a 13-fold increase in boron uptake with the micelles compared to borophenyl alanine (BPA), the conventional boron drug for BNCT. This resulted in a substantial increase in BNCT efficacy, reducing cell viability to 77% post-irradiation in micelle-treated cells, in contrast to 90% in BPA-treated cells. In vivo, melanoma-bearing mice treated with these micelles exhibited an 8-fold increase in boron accumulation in tumor tissues versus those treated with BPA, leading to prolonged tumor growth delay (5.4 days with micelles versus 3.3 days with BPA). Moreover, combining BNCT with anti-PD-L1 immunotherapy further extended the tumor growth delay to 6.6 days, and enhanced T-cell infiltration and activation at tumor sites, thereby indicating a boosted immune response. This combination demonstrates a promising approach by enhancing cytotoxic T-cell priming and mitigating the immunosuppressive effects of melanoma tumors.

Improvement of the mesitylene cold moderator at KUANS

The improvement of the neutron intensity of mesitylene cold moderator in KUANS has been conducted in two ways. One is the change of the mesitylene phase by annealing and the other is the optimization of the configuration. The change of the phase of the mesitylene was conducted by keeping the temperature of mesitylene just below its melting point for several hours. It made the cold neutron intensity about 20% larger than that of normally cooled mesitylene. For the configurational optimization, an arrangement giving highest cold neutron intensity was chosen using a Monte Carlo code. The cold neutron intensity measured with this arrangement revealed that its intensity is 3.4 times higher than that for a polyethylene moderator with room temperature.