Efficient Bacteria Killing by Cu₂WS₄ Nanocrystals with Enzyme-like Properties and Bacteria-Binding Ability

Area of Science:

• Nanotechnology
• Materials Science
• Biomedical Engineering

Background:

• Development of novel antibacterial agents is crucial to combat rising antimicrobial resistance.
• Existing nanomaterials and antibiotics have limitations in efficacy or resistance development.
• Need for agents with high efficiency, bacteria-binding capability, and reduced side effects.

Purpose of the Study:

• To synthesize and characterize copper tungsten sulfide nanocrystals (CWS NCs) for antibacterial applications.
• To evaluate the antibacterial efficacy of CWS NCs against Gram-positive and Gram-negative bacteria.
• To investigate the antibacterial mechanism and therapeutic potential of CWS NCs in vivo.

Main Methods:

• Synthesis of CWS NCs with controlled size (approx. 20 nm).
• Assessment of antibacterial activity against Staphylococcus aureus and Escherichia coli.
• Enzyme-like activity assays (oxidase and peroxidase) and reactive oxygen species (ROS) detection.
• In vivo wound infection model using methicillin-resistant Staphylococcus aureus (MRSA).

Main Results:

• CWS NCs demonstrated over 5-log inactivation of both S. aureus and E. coli at low concentrations (<2 μg mL⁻¹).
• Antibacterial activity was observed with or without ambient light, outperforming many existing nanomaterials and antibiotics.
• CWS NCs exhibited oxidase and peroxidase-like activities, facilitating ROS production for bacterial killing.
• Effective treatment of MRSA-infected wounds in animal models was achieved.

Conclusions:

• CWS NCs possess excellent antibacterial properties and bacteria-binding capabilities.
• The dual mechanism involving enzyme-like activity and ROS generation contributes to their high efficacy.
• CWS NCs show significant potential as antibacterial nanozymes for treating bacterial infections, including those caused by MRSA.