Biocompatibility evaluation of hexagonal boron nitrides on healthy mouse hippocampal cell line and their positive effect on stressed cells

In this study, hexagonal boron nitrides (hBNs) and their degradation product, boric acid (BA), are comparatively evaluated to investigate their biocompatibility and oxidative stress relieving effects on embryonic mouse hippocampal cell line (mHippoE-14). First, cell viability is assessed for a wide concentration range of 4.40-440 μg/mL of boron (B) containing hBNs and BA for 24 and 72 h exposures. Then, cell cycle, reactive oxygen species (ROS) generation, and cell death mechanisms are investigated at a concentration range of 4.4-44 μg/mL with increased incubation times. Finally, the influence of hBNs and BA on apoptotic body formation is monitored to analyze their nuclei integrity with confocal microscopy. Both hBNs and BA are found to be not cytotoxic at lower than 22 µg/mL B containing concentrations, and hBNs are much less cytotoxic compared to BA. At low concentration of hBNs, no detectable change in cell cycle, ROS production and DNA damage are observed. The study was further extended by exposing the cells to doxorubicin (DOX) to cause stress on cells before treating with hBNs and BA to investigate their positive effect on cellular metabolism. It is found that both hBNs and BA helps to increase the cell viability after the exposure to DOX. The results are envisioning the exploitation of hBNs as biocompatible agents for their possible biomedical applications including mitigating oxidative stress caused by various drugs used for neurological diseases and brain cancers. Since hBNs slowly degrade in biological media, they can be used as a controlled B releasing agent as compared to ionic BA in addition to their nanocarrier feature.