Antibacterial isoeugenol coating on stainless steel and polyethylene surfaces prevents biofilm growth.

AIMS: Pathogenic bacteria can spread between individuals or between food items via the surfaces they share. Limiting the survival of pathogens on surfaces, therefore, presents an opportunity to limit at least one route of how pathogens spread. In this study, we propose that a simple coating with the essential oil isoeugenol can be used to circumvent the problem of bacterial transfer via surfaces. METHODS AND RESULTS: Two commonly used materials, stainless steel and polyethylene, were coated by physical adsorption, and the coatings were characterized by Raman spectroscopy, atomic force microscopy and water contact angle measurements. We quantified and visualized the colonization of coated and uncoated surfaces by three bacteria: Staphylococcus aureus, Listeria monocytogenes and Pseudomonas fluorescens. No viable cells were detected on surfaces coated with isoeugenol. CONCLUSIONS: The isoeugenol coating prepared with simple adsorption proved effective in preventing biofilm formation on stainless steel and polyethylene surfaces. The result was caused by the antibacterial effect of isoeugenol, as the coating did not diminish the adhesive properties of the surface. SIGNIFICANCE AND IMPACT OF THE STUDY: Our study demonstrates that a simple isoeugenol coating can prevent biofilm formation of S. aureus, L. monocytogenes and P. fluorescens on two commonly used surfaces.

Effect of adsorbed fibronectin on the differential adhesion of osteoblast-like cells and Staphylococcus aureus with and without fibronectin-binding proteins.

The influence of fibronectin (Fn) coated surfaces patterned with poly(ethylene glycol) microgels having inter-gel spacings between 0.5 and 3.0 µm on the adhesion of Staphylococcus aureus strains with and without Fn-binding proteins and cellular adhesion/spreading was investigated. Quantitative force measurements between a S. aureus cell and a patterned surface showed that the adhesion force between the bacterium and the patterned surface increased substantially after Fn adsorption, regardless of the strain used, but decreased with decreasing inter-gel spacing. In flow-chamber experiments, the Fn-binding strain adhered at a higher rate after Fn adsorption than the strain lacking Fn-binding proteins. In both cases, the adhesion rates decreased with decreasing inter-gel spacing. Osteoblast-like cells could bind to patterned surfaces despite the microgels, and adsorbed Fn substantially amplified this effect. Even under highly non-adhesive conditions associated with closely spaced microgels, adsorbed Fn preserves a window of inter-gel spacing around 1 µm where the adhesion of staphylococcal cells is hindered while cells can still adhere and spread.

Bacterial biofilm formation versus mammalian cell growth on titanium-based mono- and bi-functional coating.

Biomaterials-associated-infections (BAI) are serious complications in modern medicine. Although non-adhesive coatings, like polymer-brush coatings, have been shown to prevent bacterial adhesion, they do not support cell growth. Bi-functional coatings are supposed to prevent biofilm formation while supporting tissue integration. Here, bacterial and cellular responses to poly(ethylene glycol) (PEG) brush-coatings on titanium oxide presenting the integrin-active peptide RGD (arginine-glycine-aspartic acid) (bioactive "PEG-RGD") were compared to mono-functional PEG brush-coatings (biopassive "PEG") and bare titanium oxide (TiO2) surfaces under flow. Staphylococcus epidermidis ATCC 35983 was deposited on the surfaces under a shear rate of 11 s-1 for 2 h followed by seeding of U2OS osteoblasts. Subsequently, both S. epidermidis and U2OS cells were grown simultaneously on the surfaces for 48 h under low shear (0.14 s-1). After 2 h, staphylococcal adhesion was reduced to 3.6-/+1.8 x 103 and 6.0-/+3.9 x 103 cm-2 on PEG and PEG-RGD coatings respectively, compared to 1.3-/+0.4 x 105 cm-2 for the TiO2 surface. When allowed to grow for 48 h, biofilms formed on all surfaces. However, biofilms detached from the PEG and PEG-RGD coatings when exposed to an elevated shear (5.6 s-1) U2OS cells neither adhered nor spread on PEG brush-coatings, regardless of the presence of biofilm. In contrast, in the presence of biofilm, U2OS cells adhered and spread on PEG-RGD coatings with a significantly higher surface coverage than on bare TiO2. The detachment of biofilm and the high cell surface coverage revealed the potential significance of PEG-RGD coatings in the context of the "race for the surface" between bacteria and mammalian cells.