@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 {734,
	title = {"Doubly selective" antimicrobial polymers: how do they differentiate between bacteria?},
	journal = {Chemistry},
	volume = {15},
	year = {2009},
	month = {2009 Nov 2},
	pages = {11710-4},
	abstract = {We have investigated how doubly selective synthetic mimics of antimicrobial peptides (SMAMPs), which can differentiate not only between bacteria and mammalian cells, but also between Gram-negative and Gram-positive bacteria, make the latter distinction. By dye-leakage experiments on model vesicles and complementary experiments on bacteria, we were able to relate the Gram selectivity to structural differences of these bacteria types. We showed that the double membrane of E. coli rather than the difference in lipid composition between E. coli and S. aureus was responsible for Gram selectivity. The molecular-weight-dependent antimicrobial activity of the SMAMPs was shown to be a sieving effect: while the 3000 g mol(-1) SMAMP was able to penetrate the peptidoglycan layer of the Gram-positive S. aureus bacteria, the 50000 g mol(-1) SMAMP got stuck and consequently did not have antimicrobial activity.},
	keywords = {Anti-Infective Agents, Biomimetic Materials, Escherichia coli, Microbial Sensitivity Tests, Peptidoglycan, Polymers, Staphylococcus aureus},
	issn = {1521-3765},
	doi = {10.1002/chem.200802558},
	author = {Lienkamp, Karen and Kumar, Kushi-Nidhi and Som, Abhigyan and N{\"u}sslein, Klaus and Tew, Gregory N}
}
