Synthesis and Characterization of Boron Carbide Nanoparticles as Potential Boron-Rich Therapeutic Carriers

Abstract

Boron carbide is one of the hardest materials in the world which can be synthesized by various methods. The most common one is a carbothermic or magnesiothermic reduction of B2O3 performed at high temperatures, where the obtained powder still requires grinding and purification. The goal of this research is to present the possibility of synthesizing B4C nanoparticles from elements via vapor deposition and modifying the morphology of the obtained powders, particularly those synthesized at high temperatures. B4C nanoparticles were synthesized in the process of direct synthesis from boron and carbon powders heated at the temperature of 1650 °C for 2 h under argon and characterized by using scanning electron microscopy, transmission electron microscopy, atomic force microscopy, X-ray diffraction analysis, and dynamic light scattering measurements. The physicochemical characteristics of B4C nanoparticles were determined, including the diffusion coefficients, hydrodynamic diameter, electrophoretic mobilities, and zeta potentials. An evaluation of the obtained B4C nanoparticles was performed on several human and mouse cell lines, showing the relation between the cytotoxicity effect and the size of the synthesized nanoparticles. Assessing the suitability of the synthesized B4C for further modifications in terms of its applicability in boron neutron capture therapy was the overarching goal of this research.

Macrophages as carriers of boron carbide nanoparticles dedicated to boron neutron capture therapy

“…In our previous work, we performed a preliminary toxicity assessment of boron carbide preparations (B 4 C 1 and B 4 C 2) on cells originating from cell lines such as RAW264.7 and J774A.1 macrophages and JAWS II dendritic cells [ 18 ]. We decided to expand the research to include bone marrow-derived macrophages (BMDM), as it brings us closer to the in vivo model and provides a good basis for further experiments.…”

“…Our previous toxicity studies showed that RAW264.7 and J774A.1 macrophages were more sensitive to boron carbide preparations compared to JAWS II dendritic cells, especially to B 4 C 2 preparation containing larger nanoparticles [ 18 ]. Thus, similarly to determine the effect of boron carbide preparations on the viability of M0, M1 and M2 bone marrow-derived macrophages after 72 h of incubation, the MTT assay was performed (Fig.…”

“…This phenomenon can be associated with the larger size of nanoparticles in B 4 C 2, because as is well known, the kinetics of compound internalization by phagocytic cells depends on their parameters such as size, shape, surface chemical composition and mechanical properties [ 4 ]. In our previous work, we described in detail the synthesis process of both boron carbide preparations and performed physicochemical characteristics, showing that both preparations differ, among others, in the size of nanoparticles, zeta potential, and hydrodynamic diameter [ 18 ]. Our results correspond with research that confirmed an increase in the uptake of gold nanoparticles by J774A.1 macrophages in a size-dependent manner [ 26 ], similarly, in the case of gliadin nanoparticles [ 27 ].…”

“…Two boron carbide preparations were synthesized, differing in physicochemical properties such as nanoparticle size (32 ± 10 nm for preparation 1 - B 4 C 1, and 80 ± 30 nm for preparation 2 - B 4 C 2), zeta potential and hydrodynamic diameter, as already described in our previous work [ 18 ].…”

“…The half maximal inhibitory concentration (IC 50 ) value was calculated using GraphPad Prism 8 software (GraphPad Software). MTT cell viability assay for lines: RAW264.7, J774A.1 and JAWS II was performed and described in our previous work by Kozień et al [ 18 ]. MTT assays were performed in two independent experiments, each in triplicate.…”