title: Bacterial biofilm formation versus mammalian cell growth on titanium-based mono- and bi-functional coating.
abstract: 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.
authors.affiliation: Department of Biomedical Engineering, University Medical Center Groningen and University of Groningen, P.O. Box 196, 9700 AD Groningen, The Netherlands.
authors.forename: G
authors.initials: G
authors.lastname: Subbiahdoss
authors.forename: B
authors.initials: B
authors.lastname: Pidhatika
authors.forename: G
authors.initials: G
authors.lastname: Coullerez
authors.forename: M
authors.initials: M
authors.lastname: Charnley
authors.forename: R
authors.initials: R
authors.lastname: Kuijer
authors.forename: H C
authors.initials: HC
authors.lastname: van der Mei
authors.forename: M
authors.initials: M
authors.lastname: Textor
authors.forename: H J
authors.initials: HJ
authors.lastname: Busscher
mesh_terms: D000818:Animals; D001422:Bacterial Adhesion; D018441:Biofilms / Q000254:growth & development*; D002448:Cell Adhesion; D049109:Cell Proliferation; D020099:Coated Materials, Biocompatible / Q000737:chemistry* / Q000627:therapeutic use; D017053:Infection Control; D008422:Materials Testing; D009842:Oligopeptides; D010006:Osteoblasts / Q000166:cytology*; D011092:Polyethylene Glycols / Q000494:pharmacology / Q000627:therapeutic use; D013212:Staphylococcus epidermidis / Q000187:drug effects / Q000254:growth & development; D023822:Tissue Engineering / Q000379:methods*; D014025:Titanium / Q000494:pharmacology* / Q000627:therapeutic use
chemical_list: D020099:Coated Materials, Biocompatible; D009842:Oligopeptides; C009495:titanium dioxide; D011092:Polyethylene Glycols; C047981:arginyl-glycyl-aspartic acid; D014025:Titanium