Inflammatory response induced by black phosphorus nanosheets in mice and macrophages

Black phosphorus nanosheets (BPs) belong to a type of two-dimensional layered materials and have garnered significant attention due to their diverse potential in nanomedical applications. Until recently, BPs have been increasingly applied in the biomedical field due to their excellent physical and chemical properties, as well as good biocompatibility. However, there has not been much concern about their potential toxic effects or biological effects on physiological systems. Herein, we found that BPs induced a reversible inflammatory response in mice, and then the detailed multifactorial inflammatory effects were studied among mouse macrophages. The treatment with BPs can induce higher levels of reactive oxygen species (ROS) in mouse bone marrow-derived macrophages (BMDMs), leading to significant changes in cell survival rate, apoptosis, and inflammatory cytokines. The molecular levels of nuclear factor kappa-light-chain-enhancer of activated B-cells (NF-κB) and nitric oxide (NO) in the treated cells were evaluated. The results indicated a significant increase in the expression of these molecules, suggesting an expansion of inflammatory reactions. The protein expression of heme oxygenase-1 (HO-1) molecules was decreased in BP-treated groups of cells, which indicates that BPs may inhibit anti-inflammatory effects of cells, leading to aggravation of inflammation. These findings provide evidence for biointeractions of BPs in physiological systems and may be helpful for the safe use of BP-based therapies.