Revealing the biotoxicity of phosphorene oxide nanosheets based on the villin headpiece.

Phosphorene, a novel member of the two-dimensional nanomaterial family, has demonstrated great potential in biomedical applications, such as photothermal therapy, drug delivery and antibacterial. However, phosphorene is unstable and easily oxidized in an aerobic environment. In this paper, using larger-scale molecular dynamics simulations, we investigated the disruption of phosphorene oxide (PO) to the structure of a model protein, villin headpiece subdomain (HP35). It shows that the disruption of PO nanosheets to the protein structure is enhanced with increasing oxidation concentration of PO, while PO's oxidation mode has very little effect on the PO-HP35 interaction. PO with a low oxidation concentration has certain biocompatibility to HP35. Oxygen atoms filling into the groove region in the puckered surface of phosphorene enhance the dispersion interaction between phosphorene and HP35, which enhances the disruption of phosphorene to the structure of HP35. Compared with the dispersion interaction, the electrostatic interaction between PO and the protein has a negligible effect on the structural damage of HP35. These findings might shed light on the biological toxicity of PO nanosheets and would be helpful for future potential biomedical applications of PO nanosheets, such as nanodrugs and antibacterial agents.

A novel strategy for the efficient decomposition of toxic sodium cyanate by hematite.

Toxic sodium cyanate is always present in cyanide-contaminated waste. A new technology for the efficient decomposition of toxic sodium cyanate by hematite was first proposed in this study. The decomposition of sodium cyanate under various atmospheres has been studied. Studies show that sodium cyanate decomposes above 782 °C in Ar and above 627 °C in air. Sodium cyanate does not decompose even roasted at 400 °C for 120 min in air. Hematite does not promote the decomposition of sodium cyanate in Ar. However, almost all sodium cyanate decomposes efficiently at 400 °C and the mass ration of hematite to sodium cyanate of 1:1 for 30 min in air or oxygen atmosphere. The increased mass ratio of hematite to sodium cyanate and roasting temperature can both favor the efficient decomposition of sodium cyanate. The efficient decomposition of sodium cyanate occurs within 30 min, and it is almost stagnant with the prolongation of roasting time. When roasted in air or oxygen in the presence of hematite, sodium cyanate decomposes to Na2CO3, CO2 and N2 and a small amount of NaNO3 and NOx. The optimal efficient decomposition of sodium cyanate is to roast above 400 °C for 30 min in air or O2 at a mass ration of hematite to sodium cyanate greater than 1:1.