Abstract
Healthcare associated infections (HCAIs) are responsible for substantial patient morbidity, mortality and economic cost. Infection control strategies for reducing rates of transmission include the use of nonwoven wipes to remove pathogenic bacteria from frequently touched surfaces. Wiping is a dynamic process that involves physicochemical mechanisms to detach and transfer bacteria to fibre surfaces within the wipe. The purpose of this study was to determine the extent to which systematic changes in fibre surface energy and nano-roughness influence removal of bacteria from an abiotic polymer surface in dry wiping conditions, without liquid detergents or disinfectants. Nonwoven wipe substrates composed of two commonly used fibre types, lyocell (cellulosic) and polypropylene, with different surface energies and nano-roughnesses, were manufactured using pilot-scale nonwoven facilities to produce samples of comparable structure and dimensional properties. The surface energy and nano-roughness of some lyocell substrates were further adjusted by either oxygen (O2) or hexafluoroethane (C2F6) gas plasma treatment. Static adpression wiping of an inoculated surface under dry conditions produced removal efficiencies of between 9.4% and 15.7%, with no significant difference (p < 0.05) in the relative removal efficiencies of Escherichia coli, Staphylococcus aureus or Enterococcus faecalis. However, dynamic wiping markedly increased peak wiping efficiencies to over 50%, with a minimum increase in removal efficiency of 12.5% and a maximum increase in removal efficiency of 37.9% (all significant at p < 0.05) compared with static wiping, depending on fibre type and bacterium. In dry, dynamic wiping conditions, nonwoven wipe substrates with a surface energy closest to that of the contaminated surface produced the highest E. coli removal efficiency, while the associated increase in fibre nano-roughness abrogated this trend with S. aureus and E. faecalis.
Highlights
Plasma modification of the nano-roughness and surface energy of fibres in nonwoven wipes was found to influence the relative removal efficiencies of common bacterial pathogens from model healthcare surfaces under dynamic wiping conditions
By adjusting exposure time (Figure 1), lyocell fabric samples were produced with significantly different surface energies (p > 0.01) ranging from 128.1 mJ m−2 for a 20 min O2 exposure to 17.1 mJ m−2 for a 20 min C2F6 exposure, the latter value being close to that obtained for untreated PP fabric (19.2 mJ m−2), which is an inherently hydrophobic polymer
Longer plasma exposure times increase the nanoroughness of the fibre surface, as the sample is exposed for greater time in an energetic environment [33], It should be noted that plasma exposure alters both the surface energy and nano-roughness of a sample
Summary
Plasma modification of the nano-roughness and surface energy of fibres in nonwoven wipes was found to influence the relative removal efficiencies of common bacterial pathogens from model healthcare surfaces under dynamic wiping conditions. Surface wiping [23] and the removal of bacteria from solid surfaces by wipes has been investigated by Williams et al [13] and Ramm et al [24] These studies have described reproducible methodologies for assessing wiping efficiency, but the focus was on the macro-scale removal of bacteria in the presence of detergent or biocide, rather than on the fundamental micro- or nano-scale interactions between the fibres in the wipe, bacteria and contaminated surface. Our aim was to determine the role of fibre surface energy and surface roughness in removing bacteria from a model solid surface in the dry state without impregnation with a liquid biocide or detergent. In this way the basic design attributes of the wipe fabric can be explored in the context of bacterial decontamination. These fabrics were evaluated with fabrics composed of low surface energy, high surface nano-roughness PP fibres
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
