Deciphering the mechanisms of bacterial inactivation on HiPIMS sputtered CuxO-FeOx-PET surfaces: from light absorption to catalytic bacterial death.
Deciphering the mechanisms of bacterial inactivation on HiPIMS sputtered CuxO-FeOx-PET surfaces: from light absorption to catalytic bacterial death.
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DOI：
10.1021/acsami.9b17380
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发表时间：
2019-11
影响因子：
9.5
通讯作者：
A. Graf;Jake Finkel;A. Chauvet;S. Rtimi
中科院分区：
文献类型：
--
作者：
A. Graf;Jake Finkel;A. Chauvet;S. Rtimi
The production of non-toxic, affordable and efficient antibacterial surfaces is key to the wellbeing of our societies. In this aim, antibacterial thin films have been prepared using earth-abundant metals deposited using a high-power impulse magnetron sputtering (HiPIMS). The sputtered FeOx, CuxO and mixed CuxO-FeOx films exhibited fast bacterial inactivation properties under exposure to indoor light (340-720 nm) showing total bacterial inactivation within 180, 120 and 60 min, respectively. The photocatalytic mechanisms of these films were investigated, from the absorption of photons up to the bacteria's fate, by means of ultrafast transient spectroscopy, flow cytometry and malondialdehyde (MDA) quantification justifying the cell wall disruption. The primary driving force leading to bacterial inactivation was found to be the oxidative stress at the interface between the sputtered thin films and the microorganism. This was justified by using engineered porinless bacteria disabling the possible ions diffusion leading to internal bacterial inactivation. Such stress is a direct consequence of the photo-generated electron-hole pairs at the interface of the sputtered layers. By diffuse reflectance spectroscopy (DRS), we found that both FeOx and CuxO present a band gap ~2.9 eV (>425 nm), while the mixed CuxO-FeOx thin film has a band gap bellow 2.3 eV (>540 nm). The structure and atomic composition of the films was characterized by energy dispersive X-ray, X-ray photoelectron and optical spectroscopy. While the composition and metal oxidation states are distinct in all three films, the difference in photocatalytic efficiency can, at first sight, be explained as direct consequence of their absorbance and the unique interaction between Fe and Cu-oxides in the composite film.
