The emergence of nanozymes presents a promising alternative to antibiotics for reactive oxygen species-mediated broad-spectrum antimicrobial purposes, but nanozymes still face challenges of low therapeutic efficiency and poor biocompatibility. Herein, we creatively prepared a novel kind of hollow cobalt sulfide (CoS) nanospheres with a unique mesoporous structure that is able to provide numerous active sites for enzyme-like reactions. The results revealed that 50 μg/mL of CoS nanospheres exhibited strong peroxidase- and oxidase-like activities under physiological conditions with the assistance of a low concentration of hydrogen peroxide (H2O2, 100 μM) while possessing highly efficient GSH-depletion ability, which endowed CoS nanospheres with triple enzyme-like properties to combat bacterial infections. The in vitro experiments demonstrated that the CoS nanozyme displayed significant antibacterial effects against both Gram-positive Staphylococcus aureus (S. aureus) and Gram-negative Escherichia coli (E. coli). The in vivo implantation showed that the synthesized CoS effectively eliminated bacteria and promoted the recovery of infected wounds in rats while exhibiting a low cytotoxicity. This study provides a promising treatment strategy to accelerate infected wound healing.
Chemodynamic therapy (CDT), an innovative approach for treating bacterial infections, has garnered significant attention due to its ability to generate hydroxyl radicals (•OH) via Fenton/Fenton-like reactions. However, the effectiveness of CDT is considerably hindered by the limited availability of endogenous hydrogen peroxide (H2O2) and the overexpression of glutathione (GSH) within the infection microenvironment. To address these limitations, a multifunctional nanoplatform with self-supplying H2O2, GSH-depletion properties, and photothermal properties was developed through a straightforward and mild strategy. This platform employs calcium peroxide (CaO2) as the core, coated with silica (SiO2) to enhance stability and further modified with a Cu(II)-doped polydopamine (PDA) layer, forming a core–shell structured CaO2@SiO2@PDA-Cu (CSPC). The Cu(II) released by CSPC, combined with the H2O2 produced from CaO2 degradation, participates in a Fenton-like reaction to generate toxic •OH radicals. Additionally, Cu(II)-mediated redox reactions deplete overexpressed GSH, thereby enhancing CDT efficacy. Upon coordination with Cu(II), the photothermal properties of PDA are significantly enhanced, achieving a photothermal conversion efficiency of up to 43%. The hyperthermia induced by photothermal therapy (PTT) further increases •OH production, augmenting CDT. The CSPC nanomaterials demonstrated outstanding synergistic photothermal bactericidal activity against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) at 60 μg/mL, achieving complete eradication. Moreover, CSPC eliminated 65.90 ± 3.46% of the S. aureus biofilm under near-infrared (NIR) irradiation. In vivo experiments demonstrated that CSPC treatment effectively eradicated bacteria, with a bacterial survival rate of 6.56 ± 3.28%, and accelerated wound healing, reducing the relative wound size to 7.0 ± 2.6%. Therefore, this study successfully developed versatile nanomaterials that significantly enhance the PTT/CDT dual-mode antibacterial performance.
Fe-CDs-PEG, leading to the occurrence of excess iron, iron metabolism disorder, GSH consumption, reactive oxygen species (ROS) accumulation, and activated the ferroptosis pathway, can enhance radiotherapy sensitivity by inducing ferroptosis in lung cancer cells. This study provides a new idea for effective therapy of lung cancer.
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