Carbon-Bridged-Mediated Electron Transfer in Cu₂O-ZnO Nanocomposites Enabling ROS-Driven Antimicrobial Activity

Area of Science:

• Materials Science
• Nanotechnology
• Interface Science

Background:

• Engineering electronic interactions between distinct metal oxides without altering their structure is a significant challenge.
• Existing Cu2O-ZnO systems often involve heterojunctions or mixing, limiting unexplored approaches like carbon-mediated coupling.

Purpose of the Study:

• To develop and characterize carbon-bridged Cu2O/ZnO nanocomposites (Cu2O-C-ZnO NCs) with strong interfacial electronic coupling.
• To investigate the impact of this coupling on charge transfer, ion release, and reactive oxygen species (ROS) generation.
• To evaluate the antibacterial and antialgal efficacy of the synthesized nanocomposites.

Main Methods:

• Synthesis of Cu2O-C-ZnO NCs using gallic acid-derived carbon framework with Cu2O and ZnO nanoparticles.
• Structural and compositional analysis (e.g., X-ray photoelectron spectroscopy) to confirm structure and electronic coupling.
• In vitro assays to assess antibacterial and antialgal activity, supported by enzymatic and cellular assays.

Main Results:

• Successfully synthesized Cu2O-C-ZnO NCs with crystalline Cu2O and ZnO integrated within a carbon matrix.
• Confirmed interfacial electronic coupling and charge redistribution via core level shifts in XPS, without lattice fusion.
• Demonstrated enhanced controlled release of metal ions and ROS generation.
• Achieved significant antibacterial activity against Gram-negative and Gram-positive bacteria and antialgal activity against freshwater species.

Conclusions:

• Carbon-mediated interfacial electronic coupling is a viable strategy for creating functional multicomponent oxide systems.
• This approach enables control over surface reactivity while preserving the structural integrity of individual oxide components.
• The Cu2O-C-ZnO NCs show promise for applications requiring antimicrobial and antialgal properties.