@article {1416,
	title = {Antimicrobial surfaces containing cationic nanoparticles: how immobilized, clustered, and protruding cationic charge presentation affects killing activity and kinetics.},
	journal = {Colloids Surf B Biointerfaces},
	volume = {125},
	year = {2015},
	month = {2015 Jan 1},
	pages = {255-63},
	abstract = {<p>This work examines how the antimicrobial (killing) activity of net-negative surfaces depends on the presentation of antimicrobial cationic functionality: distributed versus clustered, and flat clusters versus raised clusters. Specifically, the ability to kill Staphylococcus aureus by sparsely distributed 10 nm cationic nanoparticles, immobilized on a negative surface and backfilled with a PEG (polyethylene glycol) brush, was compared with that for a dense layer of the same immobilized nanoparticles. Additionally, sparsely distributed 10 nm poly-L-lysine (PLL) coils, adsorbed to a surface to produce flat cationic \&quot;patches\&quot; and backfilled with a PEG brush were compared to a saturated adsorbed layer of PLL. The latter resembled classical uniformly cationic antimicrobial surfaces. The protrusion of the cationic clusters substantially influenced killing but the surface concentration of the clusters had minor impact, as long as bacteria adhered. When surfaces were functionalized at the minimum nanoparticle and patch densities needed for bacterial adhesion, killing activity was substantial within 30 min and nearly complete within 2 h. Essentially identical killing was observed on more densely functionalized surfaces. Surfaces containing protruding (by about 8 nm) nanoparticles accomplished rapid killing (at 30 min) compared with surfaces containing similarly cationic but flat features (PLL patches). Importantly, the overall surface density of cationic functionality within the clusters was lower than reported thresholds for antimicrobial action. Also surprising, the nanoparticles were far more deadly when surface-immobilized compared with free in solution. These findings support a killing mechanism involving interfacial stress.</p>
},
	issn = {1873-4367},
	doi = {10.1016/j.colsurfb.2014.10.043},
	author = {Fang, Bing and Jiang, Ying and N{\"u}sslein, Klaus and Rotello, Vincent M and Santore, Maria M}
}
@article {733,
	title = {Antimicrobial polymers prepared by ring-opening metathesis polymerization: manipulating antimicrobial properties by organic counterion and charge density variation.},
	journal = {Chemistry},
	volume = {15},
	year = {2009},
	month = {2009 Nov 2},
	pages = {11715-22},
	abstract = {The synthesis and characterization of a series of poly(oxanorbornene)-based synthetic mimics of antimicrobial peptides (SMAMPs) is presented. In the first part, the effect of different organic counterions on the antimicrobial properties of the SMAMPs was investigated. Unexpectedly, adding hydrophobicity by complete anion exchange did not increase the SMAMPs{\textquoteright} antimicrobial activity. It was found by dye-leakage studies that this was due to the loss of membrane activity of these polymers caused by the formation of tight ion pairs between the organic counterions and the polymer backbone. In the second part, the effect of molecular charge density on the biological properties of a SMAMP was investigated. The results suggest that, above a certain charge threshold, neither minimum inhibitory concentration (MIC90) nor hemolytic activity (HC50) is greatly affected by adding more cationic groups to the molecule. A SMAMP with an MIC90 of 4 microg mL(-1) against Staphylococcus aureus and a selectivity (=HC50/MIC90) of 650 was discovered, the most selective SMAMP to date.},
	keywords = {Anti-Infective Agents, Biomimetic Materials, Cations, Diamines, Hemolysis, Hydrophobic and Hydrophilic Interactions, Microbial Sensitivity Tests, Polymers},
	issn = {1521-3765},
	doi = {10.1002/chem.200900606},
	author = {Lienkamp, Karen and Madkour, Ahmad E and Kumar, Kushi-Nidhi and N{\"u}sslein, Klaus and Tew, Gregory N}
}
@article {742,
	title = {Antimicrobial polymers prepared by ROMP with unprecedented selectivity: a molecular construction kit approach.},
	journal = {J Am Chem Soc},
	volume = {130},
	year = {2008},
	month = {2008 Jul 30},
	pages = {9836-43},
	abstract = {Synthetic Mimics of Antimicrobial Peptides (SMAMPs) imitate natural host-defense peptides, a vital component of the body{\textquoteright}s immune system. This work presents a molecular construction kit that allows the easy and versatile synthesis of a broad variety of facially amphiphilic oxanorbornene-derived monomers. Their ring-opening metathesis polymerization (ROMP) and deprotection provide several series of SMAMPs. Using amphiphilicity, monomer feed ratio, and molecular weight as parameters, polymers with 533 times higher selectivitiy (selecitviy = hemolytic concentration/minimum inhibitory concentration) for bacteria over mammalian cells were discovered. Some of these polymers were 50 times more selective for Gram-positive over Gram-negative bacteria while other polymers surprisingly showed the opposite preference. This kind of "double selectivity" (bacteria over mammalian and one bacterial type over another) is unprecedented in other polymer systems and is attributed to the monomer{\textquoteright}s facial amphiphilicity.},
	keywords = {Anti-Infective Agents, Antimicrobial Cationic Peptides, Biomimetic Materials, Erythrocytes, Escherichia coli, Hemolysis, Humans, Hydrophobic and Hydrophilic Interactions, Microbial Sensitivity Tests, Molecular Weight, Norbornanes, Polymers, Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization, Staphylococcus aureus, Structure-Activity Relationship},
	issn = {1520-5126},
	doi = {10.1021/ja801662y},
	author = {Lienkamp, Karen and Madkour, Ahmad E and Musante, Ashlan and Nelson, Christopher F and N{\"u}sslein, Klaus and Tew, Gregory N}
}
@article {743,
	title = {Arsenic sequestration by nitrate respiring microbial communities in urban lake sediments.},
	journal = {Chemosphere},
	volume = {70},
	year = {2007},
	month = {2007 Dec},
	pages = {329-36},
	abstract = {Changes in microbial community composition and activity were related to geochemical conditions favoring arsenic sequestration in sediments collected from the urban, arsenic-contaminated Upper Mystic Lake. After amendment with nitrate, >94\% total soluble arsenic is sequestered by Fe(III)-(oxy)hydroxides generated in live sediments. Of this sequestered arsenic, >75\% existed as As(III), indicating As redox state alone is not responsible for changes in mobility. Arsenic sequestration was concurrent with the microbial respiration of nitrate as indicated by steady state hydrogen concentration and the presence of organisms similar to nitrate-reducing, iron-oxidizing bacteria belonging to the genus Dechloromonas in 16S rDNA clone libraries.},
	keywords = {Arsenic, Betaproteobacteria, Biodegradation, Environmental, DNA, Bacterial, DNA, Ribosomal, Fresh Water, Geologic Sediments, Massachusetts, Nitrates, Oxidation-Reduction, RNA, Ribosomal, 16S, Urbanization, Water Microbiology, Water Pollutants, Chemical},
	issn = {0045-6535},
	doi = {10.1016/j.chemosphere.2007.05.094},
	author = {Gibney, Brian P and N{\"u}sslein, Klaus}
}
