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Biomaterial-associated infections (BAI) remain a serious clinical complication, often arising from an inability of host tissue-implant integration to out-compete bacterial adhesion and growth. A commercial polymer coating based on polyethylene glycol (PEG), available in both chemically inert and NHS-activated forms (OptiChem(®)), was compared for simultaneous growth of staphylococci and osteoblasts. In the absence of staphylococci, osteoblasts adhered and proliferated well on glass controls and on the NHS-reactive PEG-based coating over 48 h, but not on the inert PEG coating. Staphylococcal growth was low on both PEG-based coatings. When staphylococci were pre-adhered on surfaces for 1.5 h to mimic peri-operative contamination, osteoblast growth and spreading was reduced on glass but virtually absent on both reactive and inert PEG-based coatings. Thus although NHS-reactive, PEG-based coatings stimulated tissue-cell interactions in the absence of contaminating staphylococci, the presence of adhering staphylococci eliminated osteoblast adhesion advantages on the PEG surface. This study demonstrates the importance of using bacterial and cellular co-cultures compared to monocultures when assessing functionalized biomaterials coatings for infectious potential., (Copyright © 2010 Elsevier Ltd. All rights reserved.)

Poly(ethylene glycol) (PEG) coatings are known to reduce microbial adhesion in terms of numbers and binding strength. However, bacterial adhesion remains of the order of 10(4)cm(-2). It is unknown whether this density of bacteria will eventually grow into a biofilm. This study investigates the kinetics of staphylococcal biofilm formation on a commercially produced, robust, cross-linked PEG-based polymer coating (OptiChem) in vitro and in vivo. OptiChem inhibits biofilm formation in vitro, and although adsorption of plasma proteins encourages biofilm formation, microbial growth kinetics are still strongly delayed compared to uncoated glass. In vivo, OptiChem-coated and bare silicone rubber samples were inserted into an infected murine subcutaneous pocket model. In contrast to bare silicone rubber, OptiChem samples did not become colonized upon reimplantation despite the fact that surrounding tissues were always culture-positive. We conclude that the commercial OptiChem coating considerably slows down bacterial biofilm formation both in vitro and in vivo, making it an attractive candidate for biomaterials implant coating., (Copyright 2009 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.)

This study examined bacterial adhesion to a new multi-component cross-linked poly(ethylene glycol)-based polymer coating that can be applied by spin-coating or spraying onto diverse biomaterials. Adhesion of five clinically isolated bacterial strains involved in biomaterial-centered infections were studied in a parallel-plate flow chamber at different shear rates and after exposure of the coating to different physiological fluids. The new chemistry inhibits non-specific biomolecular and cell binding interactions. Relative to glass, the coating reduced adhesion of all strains used in this study by more than 80%, with the exception of Escherichia coli O2K2. Reductions in adhesion of Staphylococcus epidermidis 3,399 persisted beyond 168h exposure of the coatings to phosphate buffered saline or urine, but not after exposure to protein-rich fluids as saliva and blood plasma, despite evidence from X-ray photoelectron spectroscopy that the coating integrity was not affected by exposure to these fluids. We conclude that this new coating chemistry provides beneficial properties to prevent or hinder bacterial adhesion and colonization in applications where low protein-conditions prevail.