Investigation of the Antibacterial Properties of Silver-Doped Amorphous Carbon Coatings Produced by Low Pressure Magnetron Assisted Acetylene Discharges

V. Job1, Julie Laloy2, V. Maloteau2, E. Haye1, S. Penninckx3 & S. Lucas1

1 University of Namur, Laboratoire d’Analyse par Réactions Nucléaires (LARN), Namur Institute of Structured Matter (NISM), 61 Rue de Bruxelles, 5000 Namur, Belgium
2 University of Namur, Department of Pharmacy, – 61 Rue de Bruxelles, 5000 Namur, Belgium
3 Medical Physics Department, Institut Jules Bordet, Université Libre de Bruxelles, 1 Rue Héger-Bordet, B-1000 Brussels, Belgium

The surfaces are transmission vectors of pathogens such as bacteria and viruses. By indirect contact mode between our hands and fomites, these microbes spread in our environment and contaminate us. That is all the more true in the hospitals where the immunosuppressed patients are most likely to contract infections. These latter are responsible for a significant part of morbidity and mortality worldwide, not only but also, a financier burden on our society.

The released-based plasma coatings are promising solution to this major problematic. The advantage of the release approach is to provide the anti-infectious agent locally, while avoiding any adverse toxic impact for human beings. Whatever the state it is in (ion, nanoparticles or colloids), silver (Ag) have known effects and it is used since the ancient times. Developed within the framework of nanomedicine, materials based on silver ion release have been among the most studied candidates for antimicrobial purposes.

In this work, we evaluate the possibility to produce antimicrobial, antibacterial and antiviral coating to be applied on any surfaces. Amorphous hydrogenated carbon matrix doped with silver (a-C:H:Ag) were produced by low pressure magnetron assisted acetylene discharges and deposited on stainless steel substrates. The colony-forming unit (CFU) method, LIVE/DEAD bacterial viability and modified Kirby-Bauer diffusion assays were used to assess the toxicity of this coating against Escherichia coli (Gram-negative) and Staphylococcus aureus (Gram-positive) bacteria. The antiviral properties were evaluated by infectivity assays, Tissue Culture Infectious Dose 50% (TCID50) calculated by Reed-Muench Method and a quantitative colorimetric MTS assay based on the cytopathic effect (CPE). We used a Porcin Respiratory Coronavirus (PRCV), a virus of the Coronaviridae family that shares the same common features with SARS-Cov-2. The achieved results during this work show very promising antibacterial and antiviral activities. The mechanism of action of the silver-based coatings with a carbon matrix were investigated by X-Ray Photoelectron Spectrometry (XPS) and Scanning Electron Microscopy (SEM). The results obtained suggest a crucial role of silver segregation towards the surface and formation, of nanoparticle to explain the antimicrobial effect against bacteria and viruses. The data have been published [1].

  1. Job, V.; Laloy, J.; Maloteau, V.; Haye, E.; Penninckx, S. Investigation of the Antibacterial Properties of Silver-Doped Amorphous Carbon Coatings Produced by Low Pressure Magnetron Assisted Acetylene Discharges. 2022..