Photo-responsive chitosan/Ag/MoS₂ for rapid bacteria-killing

Area of Science:

• Biomaterials Science
• Nanotechnology
• Photocatalysis

Background:

• Bacterial infections pose significant threats to human health, particularly on biomedical devices.
• Titanium (Ti) is widely used in implants, but susceptible to bacterial colonization.
• Developing effective antibacterial surface coatings is crucial for preventing implant-associated infections.

Purpose of the Study:

• To design and evaluate a chitosan (CS)-modified MoS2 coating loaded with silver nanoparticles (Ag NPs) on titanium (Ti) for rapid and efficient antibacterial activity under visible light.
• To investigate the antibacterial mechanisms, including photocatalysis and photothermal effects.
• To assess the biocompatibility of the developed coating.

Main Methods:

• Fabrication of a CS/Ag/MoS2 composite coating on a Ti surface.
• Characterization of the coating's properties, including charge and photothermal effect.
• Evaluation of antibacterial efficacy against Staphylococcus aureus and Escherichia coli under 660 nm visible light irradiation.
• Assessment of cell viability and growth using cell culture tests.

Main Results:

• The CS/Ag/MoS2 coating demonstrated high photocatalytic activity, generating reactive oxygen species (ROS) for bacterial killing.
• The coating exhibited significant antibacterial efficiency: 98.66% against Staphylococcus aureus and 99.77% against Escherichia coli after 20 min of light exposure.
• The composite coating displayed a notable photothermal effect.
• In vitro cell culture tests confirmed no adverse effects on cell growth, indicating good biocompatibility.

Conclusions:

• The CS/Ag/MoS2-Ti composite coating is a highly effective antibacterial surface system.
• Visible light-activated photocatalysis and photothermal effects contribute to rapid bacterial elimination.
• The coating demonstrates excellent biocompatibility, making it a promising strategy for preventing infections on biomedical devices and implants.