Quasi-Instantaneous Bacterial Inactivation on Cu–Ag Nanoparticulate 3D Catheters in the Dark and Under Light: Mechanism and Dynamics

Abstract

The first evidence for Cu-Ag (50%/50%) nanoparticulate hybrid coatings is presented leading to a complete and almost instantaneous bacterial inactivation in the dark (≤5 min). Dark bacterial inactivation times on Cu-Ag (50%/50%) were observed to coincide with the times required by actinic light irradiation. This provides the evidence that the bimetal Cu-Ag driven inactivation predominates over a CuO/Cu2O and Ag2O oxides inducing a semiconductor driven behavior. Cu- or Ag-coated polyurethane (PU) catheters led to bacterial inactivation needing about ∼30 min. The accelerated bacterial inactivation by Cu-Ag coated on 3D catheters sputtered was investigated in a detailed way. The release of Cu/Ag ions during bacterial inactivation was followed by inductively coupled plasma mass-spectrometry (ICP-MS) and the amount of Cu and Ag-ions released were below the cytotoxicity levels permitted by the sanitary regulations. By stereomicroscopy the amount of live/dead cells were followed during the bacterial inactivation time. By Fourier transform infrared spectroscopy (FTIR), the systematic shift of the -(CH2) band stretching of the outer lipo-polysaccharide bilayer (LPS) was followed to monitor the changes leading to cell lysis. A hydrophobic to hydrophilic transformation of the Cu-Ag PU catheter surface under light was observed within 30 min followed concomitantly to a longer back transformation to the hydrophobic initial state in the dark. Physical insight is provided for the superior performance of Cu-Ag films compared to Cu or Ag films in view of the drastic acceleration of the bacterial inactivation observed on bimetal Cu-Ag films coating PU catheters. A mechanism of bacterial inactivation is suggested that is consistent with the findings reported in this study.

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

“…The reuse of the Cu/CuOx sputtered surfaces has been reported by Rtimi et al on different substrates [27,29,30]. Although it seems that in all the tested cases a small amount (few ppb) was seen to be released, the reuse of these samples was quasi-stable for up to 5-8 cycles/reuses.…”

In Vitro and In Vivo Effectiveness of an Innovative Silver-Copper Nanoparticle Coating of Catheters To Prevent Methicillin-Resistant Staphylococcus aureus Infection

“…The donor chamber was then filled with 200 l of PBS containing 2 ppb of Ag and 20 ppb of Cu, as quantified by inductively coupled plasma-mass spectrometry (ICP-MS). These concentrations vary from the maximal amount that could be released from the catheters after intensive washing (29). The Ag/Cu suspension was then continually applied to skin samples via the donor chamber during 24 h. PBS was used as a nonirritant solution control.…”

Antimicrobial strategies for urinary catheters

“…To improve the antimicrobial efficacy, an increasing number of novel silver materials have been developed . Silver nanoparticles (Ag NPs) are one of the most attractive material for catheter coatings [Fig.…”

“…To improve the antimicrobial efficacy, an increasing number of novel silver materials have been developed. [38][39][40][41][42][43][44][45][46][47][48] Silver nanoparticles (Ag NPs) are one of the most attractive SCHEME 2. Mechanisms of bactericidal silver ion.…”

“…The Ag NPs are primarily composed of Ag 0 metal with a particle size of <100 nm and very large surfaceto-volume ratio. The microorganisms inhibition mechanism of Ag NPs is related to (1) the release of antibacterial Ag + ion from particle surface [38][39][40][41][42][43][44][45][46][47][48] ; (2) the incorporation of Ag NPs into the bacterial membrane, leading to structural damages and compromised membrane functions, including increase in permeability, disruption of regulated plasma membrane transport, and eventually, causing cell death. 49,50 In addition, silver can be combined with other active materials, showing improved antimicrobial efficacy, for instance, silver coating releasing hydroxyapatite materials, 53 52 The silver-impregnated catheters will continue to play an important role, owing to its broad-spectrum antimicrobial ability, simple preparation, and less side effects.…”