Formation of extracellular polymeric substances (EPS) is a crucial step for bacterial biofilm growth. Dependence of EPS composition on the growth substrate and the conditioning of the latter is thus of primary importance. Here, we present results of studies on the growth of biofilms of two different strains each, of the Gram negative bacteria Escherichia coli and Klebsiella pneumoniae, on four polymers used commonly in indwelling medical devices – Polyethene, Polypropylene, Polycarbonate, and Polytetrafluoroethylene immersed in Bovine Serum Albumin (BSA) for 24 hrs. The polymer substrates are studied before and after immersing in BSA for 9 hrs and 24 hrs, using contact angle measurement (CAM) and Field Emission Scanning Electron Microscopy (FE-SEM) to extract, respectively, the ‘philicity’ (defined as ϕ ≡ sin (θ-90°), where θ is contact angle of the liquid on the solid at a particular temperature and ambient pressure) and spatial Hirsch parameter H (defined from the relation, F(r) ~ r^2H, where F(r) is the mean squared density fluctuation at the sample surface). H =, <0.5 or >0.5 signifies no correlation, anti-correlation, and correlation, respectively. The substrates are seen to transform from large hydrophobicity to near amphiphilicity with the formation of BSA conditioning surface layer, and the H-values distinguish the length scales of ~ 100 nm, 500 nm, and 2000 nm, with the anti-correlation increasing with length scale. Biofilms grown on the BSA-covered surfaces are studied with CAM, FE-SEM, Fourier Transform Infrared (FTIR) and Surface Enhanced Raman Spectroscopy (SERS). Most notably, the ϕ-values are independent of the bacterial species and strain but dependent on the polymer, as is also shown strikingly by both types of spectra, while H-values show some bacterial variation. Thus, the EPS composition and consequently the wetting properties of the corresponding bacterial biofilms seems to be decided by the interaction of the conditioning BSA layer with a specific polymer used as the growth substrate.

中文翻译：

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聚合物-BSA相互作用在生物膜基质中对“能力”和EPS组成的决定性作用

细胞外聚合物（EPS）的形成是细菌生物膜生长的关键步骤。因此，EPS成分对生长基质的依赖以及对后者的调节至关重要。在这里，我们介绍了革兰氏阴性菌大肠杆菌和肺炎克雷伯菌的两种不同菌株各自的生物膜生长的研究结果。，将四种常用于住宅医疗设备的聚合物-聚乙烯，聚丙烯，聚碳酸酯和聚四氟乙烯浸入牛血清白蛋白（BSA）中24小时。之前和在BSA中浸渍9个小时和24个小时后的聚合物衬底进行了研究，使用接触角测定器（CAM）和场发射扫描电子显微镜（FE-SEM），以提取，分别“亲和度”（定义为φ＆equiv;罪（θ -90°），其中θ是在特定温度和环境压力）和空间参数赫希液体在固体的接触角ħ（从关系式定义，F（R） 〜ř ^2H，其中F（R ）是样品表面的均方根密度波动）。H =，<0.5或> 0.5分别表示无相关，反相关和相关。可以看出，随着BSA调理表面层的形成，底物从大疏水性转变为接近两亲性，并且H值区分了〜100 nm，500 nm和2000 nm的长度尺度，并且反相关性随长度的增加而增加。规模。用CAM，FE-SEM，傅立叶变换红外（FTIR）和表面增强拉曼光谱（SERS）研究了在BSA覆盖的表面上生长的生物膜。最值得注意的是，在φ -值是独立的细菌种类和应变而是依赖这两种类型的光谱也令人惊讶地表明，H值显示出一些细菌变异。因此，EPS组成以及相应细菌生物膜的湿润性能似乎取决于调节BSA层与用作生长底物的特定聚合物之间的相互作用。