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Updated: Mar 23, 2026
Studying Copper Nanoparticle-Induced Programmed Cell Death in Bacteria
Published on: May 16, 2025
Bactericidal activity and mechanism of action of copper-sputtered flexible surfaces against multidrug-resistant
Myriam K S Ballo1,2, Sami Rtimi2, Stefano Mancini1
1Department of Fundamental Microbiology, Quartier Unil-Sorge, University of Lausanne, Biophore Building, CH-1015, Lausanne, Switzerland.
Abstract:
Using direct current magnetron sputtering (DCMS), we generated flexible copper polyester surfaces (Cu-PES) and investigated their antimicrobial activity against a range of multidrug-resistant (MDR) pathogens including eight Gram-positive isolates (three methicillin-resistant Staphylococcus aureus [MRSA], four vancomycin-resistant enterococci, one methicillin-resistant Staphylococcus epidermidis) and four Gram-negative strains (one extended-spectrum β-lactamase-producing [ESBL] Escherichia coli, one ESBL Klebsiella pneumoniae, one imipenem-resistant Pseudomonas aeruginosa, and one ciprofloxacin-resistant Acinetobacter baumannii). Bactericidal activity (≥3 log10 CFU reduction of the starting inoculum) was reached within 15-30 min exposure to Cu-PES. Antimicrobial activity of Cu-PES persisted in the absence of oxygen and against both Gram-positive and Gram-negative bacteria containing elevated levels of catalases, indicating that reactive oxygen species (ROS) do not play a primary role in the killing process. The decrease in cell viability of MRSA ATCC 43300 and Enterococcus faecalis V583 correlated with the progressive loss of cytoplasmic membrane integrity both under aerobic and anaerobic conditions, suggesting that Cu-PES mediated killing is primarily induced by disruption of the cytoplasmic membrane function. Overall, we here present novel antimicrobial copper surfaces with improved stability and sustainability and provide further insights into their mechanism of killing.
Insights
New flexible copper polyester (Cu-PES) surfaces demonstrate rapid antimicrobial activity against multidrug-resistant pathogens. These stable surfaces kill bacteria by disrupting the cell membrane, not via reactive oxygen species.
Area of Science:
- Materials Science
- Microbiology
- Surface Chemistry
Background:
- Multidrug-resistant (MDR) pathogens pose a significant global health threat.
- Developing novel antimicrobial surfaces is crucial for infection control.
- Copper-based materials have shown promise as antimicrobial agents.
Purpose of the Study:
- To create and characterize flexible copper polyester (Cu-PES) surfaces.
- To evaluate the antimicrobial efficacy of Cu-PES against a panel of MDR bacteria.
- To elucidate the mechanism of Cu-PES antimicrobial activity.
Main Methods:
- Flexible Cu-PES surfaces were fabricated using direct current magnetron sputtering (DCMS).
- Antimicrobial activity was tested against Gram-positive (MRSA, VRE, MRSE) and Gram-negative (ESBL E. coli, ESBL K. pneumoniae, resistant P. aeruginosa, resistant A. baumannii) MDR strains.
- Cell viability, membrane integrity, and activity under aerobic/anaerobic conditions were assessed.
Main Results:
- Cu-PES surfaces exhibited rapid bactericidal activity (≥3 log10 CFU reduction) within 15-30 minutes.
- Antimicrobial efficacy was maintained under anaerobic conditions and against bacteria with high catalase levels.
- Killing correlated with loss of cytoplasmic membrane integrity, indicating membrane disruption as the primary mechanism.
Conclusions:
- Novel, stable, and sustainable antimicrobial Cu-PES surfaces were developed.
- Cu-PES effectively kills diverse MDR bacteria through disruption of the cytoplasmic membrane.
- These findings offer new insights into copper-mediated antimicrobial mechanisms for surface applications.
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