Macro- and Nanoscale Observations of Adhesive Behavior for Several E. coli Strains (O157:H7 and Environmental Isolates) on Mineral Surfaces
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- 作者：J. B. Morrow ; R. Stratton ; H.-H. Yang ; B. F. Smets ; and D. Grasso
- 刊名：Environmental Science & Technology
- 出版年：2005
- 出版时间：September 1, 2005
- 年：2005
- 卷：39
- 期：17
- 页码：6395 - 6404
- 全文大小：293K
- 年卷期：v.39,no.17(September 1, 2005)
- ISSN：1520-5851
文摘
Subsurface biobarriers can be conceived to attenuate themigration of pathogens by adhesion to mineral surfaces.Candidate biobarrier materials of varied surface characteristics (dolomite, 
-alumina, silica, pyrophyllite, andPyrax (a composite form of pyrophyllite, mica, and silica))were tested for Escherichia coli adhesive capacity inmacroscale continuous-flow columns. Atomic forcemicroscopy (AFM) was used to determine nanoscaleinteraction energies. Predicted attractive interaction energiescorrelated well with macroscale adhesive behavior fortested E. coli strains. AFM measurements confirmed ExDLVOmodel predictions of attachment in the primary minimafor E. coli O157:H7 and two environmental isolates E. coli (UCFL-339 and UCFL-348) with MOPS conditioned Pyrax. Inmacroscale column experiments, pyrophyllite and Pyraxdemonstrated significantly higher bacterial retention, higherdeposition coefficients and lower initial cell breakthroughvalues for E. coli O157:H7 than did -alumina, silica, ordolomite (pyrophyllite, 0.93, 3.56 h-1, 3.2% ODo; Pyrax, 0.95,3.73 h-1, 2.8% ODo; -alumina, 0.74, 1.60 h-1, 33% ODo;silica, 0.63, 0.43 h-1, 73% ODo; and dolomite, 0.33, 0.17 h-1,89% ODo, respectively). Bacterial hydrophilicity impactedcell retention in Pyrax columns with the relatively hydrophobicE. coli isolate UCFL-339 (0.99, 6.13 h-1, 0.4% ODo) retainedbetter than the more hydrophilic E. coli isolate UCFL-348 (0.94, 3.70 h-1, 3.6% ODo). The strong adhesive behaviorof Pyrax was attributed to the hydrophobic (
Giwi =-32.4 mJ/m2) pyrophyllite component of the mineral. Vicinalwater appears poised between the bacterial and themineral surface during initial attachment. Overall, observedbehavior of the various E. coli strains and the selectedmineral surfaces was consistent with surface analyses,conducted at both the macro- and nanoscale.
-alumina, silica, pyrophyllite, andPyrax (a composite form of pyrophyllite, mica, and silica))were tested for Escherichia coli adhesive capacity inmacroscale continuous-flow columns. Atomic forcemicroscopy (AFM) was used to determine nanoscaleinteraction energies. Predicted attractive interaction energiescorrelated well with macroscale adhesive behavior fortested E. coli strains. AFM measurements confirmed ExDLVOmodel predictions of attachment in the primary minimafor E. coli O157:H7 and two environmental isolates E. coli (UCFL-339 and UCFL-348) with MOPS conditioned Pyrax. Inmacroscale column experiments, pyrophyllite and Pyraxdemonstrated significantly higher bacterial retention, higherdeposition coefficients and lower initial cell breakthroughvalues for E. coli O157:H7 than did -alumina, silica, ordolomite (pyrophyllite, 0.93, 3.56 h-1, 3.2% ODo; Pyrax, 0.95,3.73 h-1, 2.8% ODo; -alumina, 0.74, 1.60 h-1, 33% ODo;silica, 0.63, 0.43 h-1, 73% ODo; and dolomite, 0.33, 0.17 h-1,89% ODo, respectively). Bacterial hydrophilicity impactedcell retention in Pyrax columns with the relatively hydrophobicE. coli isolate UCFL-339 (0.99, 6.13 h-1, 0.4% ODo) retainedbetter than the more hydrophilic E. coli isolate UCFL-348 (0.94, 3.70 h-1, 3.6% ODo). The strong adhesive behaviorof Pyrax was attributed to the hydrophobic (Giwi =-32.4 mJ/m2) pyrophyllite component of the mineral. Vicinalwater appears poised between the bacterial and themineral surface during initial attachment. Overall, observedbehavior of the various E. coli strains and the selectedmineral surfaces was consistent with surface analyses,conducted at both the macro- and nanoscale.