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Abstract Sami RTIMI

In recent decades, there has been a rise in infections caused by toxic pathogens and biofilms, resulting in hospital-acquired infections (HAI). Polymers are used for biomedical gadgets, serum bags, textiles, and many other applications in hospital settings. Photo-responsive coatings attracted much attention during the last decade as a novel self-disinfection method to inactivate pathogens (bacteria, viruses, fungi…) without ions release. This has prompted scientists to develop more advanced antibacterial nanostructured thin films with a uniform particle distribution, strong adhesion to the substrates, mechanical resistance, and faster bacterial/biofilm inactivation under light and in the dark. While TiO₂ films have been used for many years as bactericide films under light < 387 nm, their limited absorption of solar/visible light and slow bacterial inactivation kinetics have led researchers to explore bimetal coated surfaces (such as Cu, Ag or Fe) to shift the absorption of the films to the visible region [1-2]. Coupling TiO₂ with copper oxides showed bacterial inactivation in the minute range. provide a brief overview of the bactericidal activity of the Ag-Cu bimetal/oxides system [3].

Magnetron sputtering was recently reported to allow the preparation of advanced antibacterial uniform coatings. PES-Cu samples sputtered for 160s with a Cu-loading of 0.11 Cu wt %/wt PES and induced a 6log10 CFU loss of viability on E. coli within 15 min under dark/light conditions [4]. In the case of C. glabrata, a reduction of 4log10 CFU was observed in the dark, and a 5og10 CFU under light irradiation. The faster viability loss of the fungi C. glabrata under light compared to dark runs is attributed to the CuO/CuO on PES charge separation under light irradiation [4]. In a separate study, Ag/Cu-coated catheters were investigated for their efficacy in preventing methicillin-resistant Staphylococcus aureus (MRSA) infection in vitro and in vivo. In vitro, Ag/Cu-coated catheters pre-incubated in PBS and exposed to 10⁴-10⁷ CFU, prevented the adherence of MRSA (0-12% colonization) compared to uncoated catheters (50-100% colonization; P< 0.005). MRSA inactivation occurred instantaneously at the interface of the sputtered catheters under indoor light [5]. The sputtered surfaces were characterized using up-to-date surface science techniques and the mechanisms behind the photo-activities are illustrated in this presentation.

References

1. Milosovic et al., Nanomaterials, 2017, 7, 391.
2. Rtimi et al., Applied Catalysis B: Environmental, 2016, 191, 42–52.
3. Rtimi et al., ACS Applied Materials and Interfaces, 2016, 8, 47–55.
4. Ballo et al., J. Photochemistry and Photobiology B: Biology, 2017, 174, 229–234.
5. Ballo et al., Antimicrobial Agents and Chemotherapy, 2016, 60, 5349–5356.