Graphene-like two-dimensional materials (2DMats) show application potential in optoelectronics and biomedicine due to their unique properties. However, environmental and biological influences of these 2DMats remain to be unveiled. Here we reported the antibacterial activity of two-dimensional (2D) chemically exfoliated MoS₂ (ce-MoS₂) sheets. We found that the antibacterial activity of ce-MoS₂ sheets was much more potent than that of the raw MoS₂ powders used for the synthesis of ce-MoS₂ sheets possibly due to the 2D planar structure (high specific surface area) and higher conductivity of the ce-MoS₂. We investigated the antibacterial mechanisms of the ce-MoS₂ sheets and proposed their antibacterial pathways. We found that the ce-MoS₂ sheets could produce reactive oxygen species (ROS), different from a previous report on graphene-based materials. Particularly, the oxidation capacity of the ce-MoS₂ sheets toward glutathione oxidation showed a time and concentration dependent trend, which is fully consistent with the antibacterial behaviour of the ce-MoS₂ sheets. The results suggest that antimicrobial behaviors were attributable to both membrane and oxidation stress. The antibacterial pathways include MoS₂–bacteria contact induced membrane stress, superoxide anion (O₂˙⁻) induced ROS production by the ce-MoS₂, and the ensuing superoxide anion-independent oxidation. Our study thus indicates that the tailoring of the dimension of nanomaterials and their electronic properties would manipulate antibacterial activity.

Water-soluble, monodispersed, and bluish green-emitting Au₁₀ nanoclusters were synthesized through a simple reaction, in which histidine served as both a reducing agent and a protecting ligand. UV-visible absorption, photoluminescence, electrospray ionization (ESI) mass spectrometry, and X-ray photoelectron spectroscopy (XPS) were carried out to demonstrate the chemical composition and optical properties of the Au₁₀ clusters. The mechanism of this proposed reaction was explored and the reducing ability of histidine was proved from its imidazole group. Finally, the fluorescence of Au NCs at different reaction times, pH value, and temperature was measured in situ. Then a synthetic strategy was proposed for gold nanoclusters with a defined chemical composition, and the resulting Au₁₀ clusters stabilized by histidine are biocompatible with bioorganisms, showing a great potential for applications such as biological labeling and biosensors.

The effects of different local crystalline structures of two-dimensional (2D) MoS ₂ sheets on the performance of organic solar cells (OSCs) are studied, providing new insights towards high-performance devices.