Microscale Correlation between Surface Chemistry, Texture, and the Adhesive Strength of Staphylococcus epidermidis

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• 作者：Ray J. Emerson IV ; Torbjorn S. Bergstrom ; Yatao Liu ; Ernesto R. Soto ; Christopher A. Brown ; W. Grant McGimpsey ; Terri A. Camesano
• 刊名：Langmuir
• 出版年：2006
• 出版时间：December 19, 2006
• 年：2006
• 卷：22
• 期：26
• 页码：11311 - 11321
• 全文大小：708K
• 年卷期：v.22,no.26(December 19, 2006)
• ISSN：1520-5827

文摘

Staphylococcus epidermidis is among the most commonly isolated microbes from medical implant infections,particularly in the colonization of blood-contacting devices. We explored the relationships between surface wettabilityand root-mean-square roughness (R_q) on microbial adhesive strength to a substrate. Molecular-level interactionsbetween S. epidermidis and a variety of chemically and texturally distinct model substrata were characterized usinga cellular probe and atomic force microscopy (AFM). Substrata included gold, aliphatic and aromatic self-assembledmonolayers, and polymeric and proteinaceous materials. Substrate hydrophobicity, described in terms of the watercontact angle, was an insufficient parameter to explain the adhesive force of the bacterium for any of the surfaces.Correlations between adhesion forces and R_q showed weak relationships for most surfaces. We used an alternatemethodology to characterize the texture of the surface that is based on a fractal tiling algorithm applied to imagesof each surface. The relative area as a function of the scale of observation was calculated. The discrete bonding model(DBM) was applied, which describes the area available for bonding interactions over the full range of observationalscales contained in the measured substrate texture. Weak negative correlations were obtained between the adhesionforces and the area available for interaction, suggesting that increased roughness decreases bacterial adhesion whennano- to micrometer scales are considered. We suggest that modification of the DBM is needed in order to includediscontinuous bonding. The adhesive strength is still related to the area available for bonding on a particular scale,but on some very fine scales, the bacteria may not be able to conform to the valleys or pits of the substrate. Therefore,the bonding between the bacterium and substrate becomes discontinuous, occurring only on the tops of ridges orasperities.