Safety Profiling of Borophene Nanosheets: In Vitro and In Vivo Toxicity Investigations.

Like graphene, a well-established two dimentional (2D) material with extensive biomedical applications, borophene holds significant promise in this field. However, toxicological evaluations are crucial to establish its biosafety. The study presents in vitro cytotoxicity of borophene nanosheets (BNSs) in cancer cells and animal blood samples and in vivo toxicity studies in laboratory rats for the first time. In the acute toxicity study, different clinical and behavioral signs such as mortality, diarrhea, anxiety, respiration, salivation, etc. are investigated through visual observation, while food and water consumption, body weight changes, etc. are measured by weighing the food, water, and body weight periodically. In the subacute toxicity study, detailed hematological, serum biochemical, and histopathological evaluations are also carried out to investigate toxic effects of BNSs on blood, kidney function, liver function, and morphology of tissues of different major organs. The in vitro MTT assay in B16F10 cells and the ex vivo hemolysis assay in animal blood samples indicated no significant cytotoxic effect at the highest dose of 200 μg/mL of BNSs with 83.41 ± 9.78% cell viability and less than 5% hemolysis, respectively. The BNSs show no significant toxicological signs and symptoms even at the higher dose of 2000 mg/kg body weight during the 14-day single-dose acute oral toxicity study (as per OECD-423) and up to a dose level of 200 mg/kg BW during the 28-day repeated-dose subacute oral toxicity study (as per OECD-407) in Wistar rats. No mortality is observed in any of the groups of both acute and subacute toxicity studies. No significant alteration of different normal clinical and behavioral signs is observed during the entire study period. Hematological, serum biochemical, and histopathological evaluations also revealed no toxicity. This study demonstrates the nontoxicity and safety profile of the BNSs and thus holds considerable promise as a safe and biocompatible 2D nanomaterial for future biomedical applications.