A Kinetic Approach to Synergize Bactericidal Efficacy and Biocompatibility in Silver-Based Sol−Gel Coatings

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Zwingelstein, Thibault
Figarol, Agathe
Luzet, Vincent
Crenna, Maude
Bulliard, Xavier
Finelli, Alba
Gay, Julien
Lefèvre, Xavier
Pugin, Raphaël
Laithier, Jean-François
Silver ions are antimicrobial agents with powerful action against bacteria. Applications in surface treatments, as Ag+- functionalized sol−gel coatings, are expected in the biomedical field to prevent contaminations and infections. The potential cytotoxicity of Ag+ cations toward human cells is well known though. However, few studies consider both the bactericidal activity and the biocompatibility of the Ag+-functionalized sol−gels. Here, we demonstrate that the cytotoxicity of Ag+ cations is circumvented, thanks to the ability of Ag+ cations to kill Escherichia coli (E. coli) much faster than normal human dermal fibroblasts (NHDFs). This phenomenon was investigated in the case of two silver nitrateloaded sol−gel coatings: one with 0.5 w/w% Ag+ cations and the second with 2.5 w/w%. The maximal amount of released Ag+ ions over time (0.25 mg/L) was ten times lower than the minimal inhibition (MIC) and minimal bactericidal (MBC) concentrations (respectively, 2.5 and 16 mg/L) for E. coli and twice lower to the minimal cytotoxic concentration (0.5 mg/L) observed in NHDFs. E. coli were killed 8−18 times, respectively, faster than NHDFs by silver-loaded sol−gel coatings. This original approach, based on the kinetic control of the biological activity of Ag+ cations instead of a concentration effect, ensures the bactericidal protection while maintaining the biocompatibility of the Ag+ cation-functionalized sol−gels. This opens promising applications of silver-loaded sol− gel coatings for biomedical tools in short-term or indirect contacts with the skin.
Publication Reference
ACS Omega 2024, 9, 24574−24583