CuS NPs

In bacterial wound healing, continuous controlled oxygen delivery to injured tissue, coupled with bacterial elimination and inflammation reduction, is crucial for promoting tissue regeneration and repair. To address this, we designed a multimodal synergistic treatment strategy based on nanozymes to enable oxygen-controlled release while achieving antibacterial and anti-inflammatory effects. We developed a polydopamine-hyaluronic acid (PDA-HA) hydrogel composite system incorporating CuS NPs and CeO₂ nanozymes. Under near-infrared (NIR) irradiation, this system exhibited enhanced photothermal performance while enabling switchable O₂ and reactive oxygen species (ROS) generation. The hydrogel (termed PHCC) exhibited dual enzyme-mimic activity (peroxidase-mimic and catalase-mimic), decomposing H₂O₂ into either O₂ or hydroxyl radicals (•OH) to regulate the infection microenvironment. Additionally, photothermal therapy (PTT) was employed to enhance the dual enzyme-mimic catalytic activity through photon-induced hyperthermia. This was achieved by utilizing the ideal light absorption of the second near-infrared window of CuS NPs and the hydrogel skeleton component PDA. Both in vivo wound healing and in vitro antibacterial experiments demonstrated that photothermally enhanced ROS-mediated treatment efficiency was significantly improved. This study provides a reference for the synergistic treatment of hyperthermia-enhanced multi-enzyme activity of nanozymes to remove bacteria and promote wound healing.

Nanoparticles (NPs) are increasingly released into the environment, posing risks to living organisms. While copper sulfide NPs have been extensively studied, the toxicity of copper sulfide (CuS) NPs remains underexplored. Owing to their widespread use, it is crucial to assess their biological effects.

In this study, we used zebrafish embryos and larvae to evaluate CuS NP toxicity. Embryos were exposed to 20-100 µg/mL of CuS NPs under both dark and light conditions.

Concentrations ≥60 µg/mL caused up to 85% mortality, along with developmental abnormalities such as bent tails and pericardial edema. Under light irradiation, CuS NPs significantly elevated reactive oxygen species (ROS) production. This was evidenced by upregulated expression of antioxidant genes sod1, sod2, cat, and gpx1 in exposed embryos.

Our findings demonstrate a photoreactive toxicity mechanism: CuS NPs generate ROS under light, disrupting redox balance. This underscores the importance of environmental factors, like sunlight, in nanomaterial risk assessment. By revealing how CuS NPs affect aquatic organisms under realistic conditions, our study contributes to understanding the ecological risks these particles pose and highlights their potential implications for human health.