¹⁰Boron-doped carbon nanoparticles as delivery platforms for boron neutron capture therapy and photothermal therapy

The current clinical application of the boron drug boronophenylalanine (BPA) in BNCT faces various issues owing to its low boron loading (approximately 5%), which limits its therapeutic efficacy. Therefore, the development of boron drugs with higher boron contents is essential. Enhancing the boron content in boron drug materials is the focus of this study. Two-dimensional (2D) boron nitride-doped nano graphene (BNNG) with a high boron content of 24.97% ± 1.14% w/w was synthesized via the chemical vapor deposition (CVD) method. The size of BNNG was controlled through gradient density centrifugation. Subsequently, a strategy was proposed that leveraged a boron-nitrogen co-doping process to enhance the boron content. The resulting BN nanosheets that were grown on graphene oxide (GO) exhibited an onion-like structure. To serve as a multifunctional delivery platform, ¹⁰B-enriched BNNG was dispersed in an aqueous solution through π-π interactions with pyrene methanol polyethylene glycol carboxylate (PPEG) to form BNNG@PPEG, thus becoming water-dispersible. The synthesized multifunctional BNNG@PPEG material satisfied the requirements for BNCT, chemotherapy, and PTT with a high photothermal conversion efficiency (η = 40.552%). Under 1 W cm^-2 laser irradiation, BNNG@PPEG generated a temperature of 55 °C, and the cell survival rate significantly decreased to 36.2% ± 3.5%. Meanwhile, the thermal property of BNNG-DOX@PPEG facilitated the controlled release of doxorubicin (DOX). Under neutron irradiation, the BNNG@PPEG complex exhibited significant antitumor activity, and the cell survival rate significantly decreased to 34.82% ± 6.1%.