Roosjen Astrid, Busscher Henk J, Norde Willem, van der Mei Henny C
Department of Biomedical Engineering, University Medical Center Groningen, and University of Groningen, Antonius Deusinglaan 1, 9713 AV Groningen, The Netherlands.
Laboratory of Physical Chemistry and Colloid Science, Wageningen University, Dreijenplein 6, 6703 HB Wageningen, The Netherlands.
Microbiology (Reading). 2006 Sep;152(Pt 9):2673-2682. doi: 10.1099/mic.0.29005-0.
Most bacterial strains adhere poorly to poly(ethylene oxide) (PEO)-brush coatings, with the exception of a Pseudomonas aeruginosa strain. The aim of this study was to find factors determining whether P. aeruginosa strains do or do not adhere to a PEO-brush coating in a parallel plate flow chamber. On the basis of their adhesion, a distinction could be made between three adhesive and three non-adhesive strains of P. aeruginosa, while bacterial motilities and zeta potentials were comparable for all six strains. However, water contact angles indicated that the adhesive strains were much more hydrophobic than the non-adhesive strains. Furthermore, only adhesive strains released surfactive extracellular substances, which may be engaged in attractive interactions with the PEO chains. Atomic force microscopy showed that the adhesion energy, measured from the retract curves of a bacterial-coated cantilever from a brush coating, was significantly more negative for adhesive strains than for non-adhesive strains (P<0.001). Through surface thermodynamic and extended-DLVO (Derjaguin, Landau, Verwey, Overbeek) analyses, these stronger adhesion energies could be attributed to acid-base interactions. However, the energies of adhesion of all strains to a brush coating were small when compared with their energies of adhesion to a glass surface. Accordingly, even the adhesive P. aeruginosa strains could be easily removed from a PEO-brush coating by the passage of a liquid-air interface. In conclusion, cell surface hydrophobicity and surfactant release are the main factors involved in adhesion of P. aeruginosa strains to PEO-brush coatings.
大多数细菌菌株很难附着在聚环氧乙烷（PEO）刷涂层上，不过有一株铜绿假单胞菌菌株除外。本研究的目的是找出决定铜绿假单胞菌菌株在平行平板流动腔中是否能附着在PEO刷涂层上的因素。基于其附着力，可将三株具有附着力的铜绿假单胞菌菌株和三株无附着力的菌株区分开来，而所有六株菌株的细菌运动性和zeta电位相当。然而，水接触角表明，有附着力的菌株比无附着力的菌株疏水性更强。此外，只有有附着力的菌株会释放表面活性细胞外物质，这些物质可能与PEO链发生吸引相互作用。原子力显微镜显示，从刷涂层上细菌涂层悬臂的回缩曲线测量得到的附着力，有附着力的菌株比无附着力的菌株明显更负（P<0.001）。通过表面热力学和扩展的DLVO（Derjaguin、Landau、Verwey、Overbeek）分析，这些更强的附着力可归因于酸碱相互作用。然而，与所有菌株对玻璃表面的附着力相比，它们对刷涂层的附着力都很小。因此，即使是有附着力的铜绿假单胞菌菌株也可以通过液-气界面的通过而很容易地从PEO刷涂层上除去。总之，细胞表面疏水性和表面活性剂释放是铜绿假单胞菌菌株附着在PEO刷涂层上的主要因素。
