Beneficial effect of Cu on Ti-Nb-Ta-Zr sputtered uniform/adhesive gum films accelerating bacterial inactivation under indoor visible light

Abstract

a b s t r a c tThis article presents the evidence for the significant effect of copper accelerating the bacterial inactivation on Ti-Nb-Ta-Zr (TNTZ) sputtered films on glass up to a Cu content of 8.3 at.%. These films were deposited by dc magnetron co-sputtering of an alloy target Ti-23Nb-0.7Ta-2Zr (at.%) and a Cu target. The fastest bacterial inactivation of E. coli on this later TNTZ-Cu surface proceeded within ∼75 min. The films deposited by magnetron sputtering are chemically homogenous. The film roughness evaluated by atomic force spectroscopy (AFM) on the TNTZ-Cu 8.3 at.% Cu sample presented an RMS-value of 20.1 nm being the highest RMS of any Cu-sputtered TNTZ sample. The implication of the RMS value found for this sample leading to the fastest interfacial bacterial inactivation kinetics is also discussed. Values for the Young's modulus and hardness are reported for the TNTZ films in the presence of various Cu-contents. Evaluation of the bacterial inactivation kinetics of E. coli under low intensity actinic hospital light and in the dark was carried out. The stable repetitive bacterial inactivation was consistent with the extremely low Cu-ion release from the samples of 0.4 ppb. Evidence is presented by the bacterial inactivation dependence on the applied light intensity for the intervention of Cu as semiconductor CuO during the bacterial inactivation at the TNTZ-Cu interface. The mechanism of CuO-intervention under light is suggested based on the pH/and potential changes registered during bacterial disinfection.

Indoor Light Enhanced Photocatalytic Ultra-Thin Films on Flexible Non-Heat Resistant Substrates Reducing Bacterial Infection Risks

“…Their results are consistent with the long-range mobility of conduction band electrons being strongly influenced by grain boundaries. Consequently, optimizing the crystals/particles size while keeping high enough surface area will be an significant way onward [66][67][68][69].…”

Innovative Ti1–xNbxN–Ag Films Inducing Bacterial Disinfection by Visible Light/Thermal Treatment

“…Highly pathogenic biofilms can strongly adhere to textiles, glass surfaces, prostheses, catheters, dental implants, and metal plates. − Ag film morphology and grain size have been addressed in Ag films leading to bacterial inactivation . More advanced and effective antibacterial surfaces are a subject of timely interest, and in this direction silver and copper nanoparticles have recently been addressed in studies reporting antibacterial surfaces/films, − carbon nanotubes, , diamond-like carbon, , metal oxides, − nitrides, − and oxynitrides. − …”

Architectured Cu–TNTZ Bilayered Coatings Showing Bacterial Inactivation under Indoor Light and Controllable Copper Release: Effect of the Microstructure on Copper Diffusion

“…In our previous studies [13][14][15], we reported the mechanical properties of a superelastic Ti-based GMTF showing increased bacterial inactivation under light concomitant to a biocompatible property in darkness [16,17]. We also showed the effect of copper content on the structure, morphology, and mechanical properties of GMTF [18]. We also showed that the TNTZ-Cu 8.3 at % Cu sample with the highest roughness (RMS value of 20.1 nm) led to the highest bactericidal activity.…”