Electronic Structure Modulation of Ag2 S by Vacancy Engineering for Efficient Bacterial Infection.

Vacancy engineering can modulate the electronic structure of the material and thus contribute to the formation of coordination unsaturated sites, which makes it easier to act on the substrate. Herein, Ag2 S and Ag2 S-100, which mainly have vacancy associates VAgS and VAgSAg , respectively, are prepared and characterized by positron annihilation spectroscopy. Both experimental and theoretical calculation results indicate that Ag2 S-100 exhibits excellent antibacterial activity due to its appropriate bandgap and stronger bacteria-binding ability, which endow it with a superior antibacterial activity compared to Ag2 S in the absence of light. The in vivo antibacterial experiment using a mouse wound-infection model further confirms that Ag2 S-100 has excellent antibacterial and wound-healing properties. This research provides clues for a deeper understanding of modulating electronic structures through vacancy engineering and develops a strategy for effective treatment of bacterial infections.

Efficient photothermal and photodynamic synergistic antibacterial therapy of Cu7S4 nanosheets regulated by facet engineering.

The surface arrangements of nanomaterials can regulate their electronic structure, which will tune physicochemical properties of materials to various applications. In this study, two Cu7S4 nanosheets with (304) and (224) exposed facets were synthesized, respectively, and their antibacterial activity of different facets for replacing antibiotics to solve seriously drug-resistant bacteria were further measured. Experimental and theoretical computation results unveiled that Cu7S4 with (224) exposed facet exhibited excellent antibacterial activity through synergetic photodynamic and photothermal therapy against Gram-positive Bacillus subtilis, Gram-negative Escherichia coli and drug-resistant Pseudomonas aeruginosa under near-infrared light (808 nm) irradiation. Furthermore, the antibacterial agents strongly inhibit mouse skin infection by drug-resistant Pseudomonas aeruginosa cells. The findings provide an efficient antibacterial strategy and might advance the method of designing and producing highly effective antibacterial nanomaterials through facet engineering.

Near-infrared responsive sulfur vacancy-rich CuS nanosheets for efficient antibacterial activity via synergistic photothermal and photodynamic pathways.

Defect engineering has been proven to be an effective approach for electronic structure modulation and plays an important role in the photocatalytic performance of nanomaterials. In this study, a series of CuS nanosheet sulfur vacancies (VS) are constructed by a simple hydrothermal synthesis method. The CuS with the highest VS concentration exhibits strong antibacterial performance, achieving bactericidal rates of 99.9% against the Gram-positive Bacillus subtilis and Gram-negative Escherichia coli bacteria under 808 nm laser irradiation. Under illumination, the temperature of the catalyst increases from 23.5 °C to 53.3 °C, and with a high photothermal conversion efficiency of 41.8%. For E. coli and B. subtilis, the reactive oxygen species (ROS) production that is induced by the CuS group is 8.6 and 9.6 times greater, respectively, than that of the control group. The presence of VS facilitates the enhancement of the light absorption capacity and the separation efficiency of electron-hole pairs, thereby resulting in improved photocatalytic performance. The synergistic effect of photothermal therapy (PTT) and photodynamic therapy (PDT) is aimed at causing oxidative damage and leading to bacterial death. Our findings provide an effective antibacterial strategy and offer new horizons for the application of CuS catalysts with VS in the NIR region.

SnS Nanosheets for Rapid and Effective Bacteria Sterilization Under Near-infrared Irradiation.

Today, the threat of pathogenic bacterial infection worldwide that leads to the increase of mortality rate strongly demands the development of new antibacterial agents that can kill bacteria quickly and effectively. Although there are a lot of antibacterial agents that have been developed so far, few studies on the antibacterial performance of SnS have been investigated at 808 nm laser. Here, we synthesized SnS nanosheets with strong near-infrared absorption performance and excellent antibacterial performance via a simple solvothermal synthesis route. The as-prepared SnS nanosheets showed excellent photothermal conversion efficiency (38.7 %), photodynamic performance, and photostability, and at the same time 99.98 % and 99.7 % sterilization effect against Gram-negative Escherichia coli (E. coli) and Gram-positive Bacillus subtilis (B. subtilis) under near-infrared irradiation (808 nm, 1.5 W/cm2 ). This study suggests that SnS nanosheets could be a promising candidate for antibacterial therapy owing to the synergetic effects of photothermal and photodynamic performance.