Boron oxide/human albumin nanoparticles as potential boron carrier for BNCT: initial pilot study to determine the concentration of B in the solution using the ICP-OES technique

RAMOS; PALMIERI; CANDIA; ACHILLI, E.; GRASSELLI, M.; GARABALINO, M

Granada

Congreso; ICNCT19 19th International Congress on Neutron Capture Therapy; 2021

International Atomic Energy Agency

Introduction: Multiple international efforts are aimed at the development of new boron carriers for Boron Neutron Capture Therapy (BNCT) with a greater therapeutic potential than the existing compounds. The development of new boron carriers seeks to maximize the total boron content in the tumor and enhance selective uptake in different tumor populations of a heterogeneous tumor. Considering the need to obtain compounds enriched in 10 B that are compatible with biological systems, hybrid nanoparticles (HNPs) composed of B and Human Serum Albumin (HSA) were prepared. The boron concentration of solutions of HNPs was measured by means of the ICP-OES technique. Aim: to perform an initial pilot study to determine the concentration of B using the ICP-OES technique of solutions of HNPs with or without HSA as potential boron carrier compounds for BNCT. Materials and methods: the HNPs were synthesized at the National University of Quilmes from boron oxide and oleic acid and subsequently coated with HSA to confer biocompatibility. Characterization was carried out using DLS, TEM, FTIR techniques. Two HNPs solutions, with or without HSA, were processed by nitric acid digestion at 100ºC for 2 h and sonicated at 60ºC for 1 h for boron measurement by atomic emission spectroscopy (ICP-OES) at the Radiobiology Department-CNEA. For the quantitative measurement of the [B in the samples, the atomic emission spectra of the lines 208.889 and 249.677 nm were analyzed. Results: The HSA-coated HNPs exhibited a core/shell type spherical nanometric structure, with an average hydrodynamic diameter of 40 nm. Furthermore, the presence of the protein coating was confirmed. On the other hand, NPs without HSA show an average hydrodynamic size of 20 nm. The mean B concentration of the HNPs, with or without HSA, were 199  209 ppm (n=3) and 12068  3590 ppm (n=3), respectively. Conclusion: these pilot results would demonstrate that the B concentration of the solution of borated nanoparticles without coating of HSA was ≥ 10000 ppm, similar to the solutions of other borated compounds employed successfully with different administration protocols in biodistribution assays in animal models (ex: BPA, BSH, BA, GB-10). Therefore, the HNPs without HSA would be a potential boron carrier for in vitro and in vivo BNCT studies. On the other hand, the low boron concentration values for the solution of the HNPs with human serum albumin warrant future B measurement tests with different digestion protocols.