@article {1424,
	title = {How Bacteria Adhere to Brushy PEG Surfaces: Clinging to Flaws and Compressing the Brush.},
	journal = {Macromolecules},
	volume = {45},
	year = {2012},
	month = {2012 Oct 23},
	pages = {8373-8381},
	abstract = {<p>This study examined the compression of solvated polymer brushes on bioengineered surfaces during the initial stages of Staphylococcus Aureus (S. aureus) adhesion from gentle flow. A series of PEG [poly(ethylene glycol)] brushes, 7 to 17 nm in height and completely non-adhesive to proteins and bacteria, were modified by the incorporation of sparse isolated ~10 nm cationic polymer \&quot;patches\&quot; at their bases. These nanoscale regions, which lacked PEG tethers, were electrostatically attractive towards negative bacteria or proteins. S. aureus drawn to the interface by multiple adhesive patches compressed the PEG brush in the remaining contact region. The observed onset of bacterial or fibrinogen capture with increases in patch content was compared with calculations. Balancing the attraction energy (proportional to the number of patches engaging a bacterium during capture) against steric forces (calculated using the Alexander-DeGennes treatment) provided perspective on the brush compression. The results were consistent with a bacteria-surface gap on the order of the Debye length in these studies. In this limit of strong brush compression, structural features (height, persistence length) of the brush were unimportant so that osmotic pressure dominated the steric repulsion. Thus, the dominant factor for bacterial repulsion was the mass of PEG in the brush. This result explains empirical reports in the literature that identify the total PEG content of a brush as a criteria for prevention of bioadhesion, independent of tether length and spacing, within a reasonable range for those parameters. Bacterial capture was also compared to that of protein capture. It was found, surprisingly, that the patchy brushes were more protein-than bacteria-resistant. S. aureus adhesion driven by patches within otherwise protein-resistant PEG brushes was explained by the bacteria\&$\#$39;s greater tendency to compress large areas of brush to interact with many patches. By contrast, proteins are thought to penetrate the brush at a few sites of PEO-free patches. The finding provides a mechanism for the literature reports that in-vitro protein resistance is a poor predictor of in-vitro implant failure related to cell-surface adhesion.</p>
},
	issn = {0024-9297},
	doi = {10.1021/ma300981r},
	author = {Gon, S and Kumar, Kushi-Nidhi and N{\"u}sslein, Klaus and Santore, Maria M}
}
@article {736,
	title = {Hydrogenotrophic denitrification and perchlorate reduction in ion exchange brines using membrane biofilm reactors.},
	journal = {Biotechnol Bioeng},
	volume = {104},
	year = {2009},
	month = {2009 Oct 15},
	pages = {483-91},
	abstract = {Halophilic (salt loving), hydrogenotrophic (H(2) oxidizing) denitrifying bacteria were investigated for treatment of nitrate (NO3-) and perchlorate (ClO4-) contaminated groundwater and ion exchange (IX) brines. Hydrogenotrophic denitrifying bacteria were enriched from a denitrifying wastewater seed under both halophilc and non-halophilc conditions. The cultures were inoculated into bench-scale membrane biofilm reactors (MBfRs) with an "outside in" configuration, with contaminated water supplied to the lumen of the membranes and H(2) supplied to the shell. Abiotic mass transfer tests showed that H(2) mass transfer coefficients were lower in brines than in tap water at highest Reynolds number, possibly due to increased transport of salts and decreased H(2) solubility at the membrane/liquid interface. An average NO3- removal efficiency of 93\% was observed for the MBfR operated in continuous flow mode with synthetic contaminated groundwater. Removal efficiencies of 30\% for NO3- and 42\% for ClO4- were observed for the MBfR operated with synthetic IX brine in batch operating mode with a reaction time of 53 h. Phylogenetic analysis focused on the active microbial community and revealed that halotolerant, NO3- -reducing bacteria of the bacterial classes Gamma-Proteobacteria and Sphingobacteria were the metabolically dominant members within the stabilized biofilm. This study shows that, despite decreased H(2) transfer under high salt conditions, hydrogenotrophic biological reduction may be successfully used for the treatment of NO3- and ClO- in a MBfR.},
	keywords = {Bacteroidetes, Biofilms, Cluster Analysis, DNA, Bacterial, DNA, Ribosomal, Gammaproteobacteria, Hydrogen, Ion Exchange, Membranes, Molecular Sequence Data, Nitrites, Oxidation-Reduction, Perchloric Acid, Phylogeny, RNA, Ribosomal, 16S, Sequence Analysis, DNA, Water Pollutants, Chemical, Water Purification},
	issn = {1097-0290},
	doi = {10.1002/bit.22414},
	author = {Sahu, Ashish K and Conneely, Teresa and N{\"u}sslein, Klaus and Ergas, Sarina J}
}
@article {738,
	title = {Hydrophilic modifications of an amphiphilic polynorbornene and the effects on its hemolytic and antibacterial activity.},
	journal = {Biomacromolecules},
	volume = {10},
	year = {2009},
	month = {2009 Feb 9},
	pages = {353-9},
	abstract = {Here we report the modification of an amphiphilic antibacterial polynorbornene, Poly3, via incorporation of hydrophilic, biocompatible groups. The sugar, zwitterionic, and polyethylene glycol based moieties were incorporated in varying ratios by copolymerization and postpolymerization techniques. Well-defined copolymers with molecular weights of 3 kDa and narrow polydispersity indices ranging from 1.08 to 1.15 were obtained. The effects of these modifications on the biological activity of these polymers were analyzed by determining their minimum inhibitory concentrations (MIC) and their hemolytic activities (HC50).},
	keywords = {Anti-Bacterial Agents, Bacteria, Biocompatible Materials, Carbohydrates, Hemolysis, Microbial Sensitivity Tests, Plastics, Polyethylene, Static Electricity},
	issn = {1526-4602},
	doi = {10.1021/bm801129y},
	author = {Colak, Semra and Nelson, Christopher F and N{\"u}sslein, Klaus and Tew, Gregory N}
}
