Antimicrobial contact kill

Fig. 9 Example of a contact-killing and microbe-repelling surface, (a) Antimicrobial cationic polyW.iV-dimethyl-iVTethoxycarbonylmethyll-iV-P -tniethacryloyloxylethyll-ammonium bromide) left structure) effectively kills bacteria, (b) The polymer is converted into the corresponding nonfouling zwitterionic derivative (right structure) upon hydrolysis, (c) Dead bacteria remaining on the surface are repelled from the nonfouling surface, (d) The zwitterionic surface itself is highly resistant to bacterial adhesion. Reproduced and adapted from [136]...

Contact killing antimicrobial articles, devices and formulations are described which kill microorganisms... 

Many articles are treated with antimicrobials to kill or inhibit the growth of bacteria and/or mold. Treated articles are subject to a variety of test methods used to confirm antimicrobial activity. Some of these articles come in contact with the human body and therefore must be tested in order to assess their biocompatibility under conditions of intended use. Determining the efficacy and biocompatibility of these treated articles is crucial. 

Repelling microbes or killing them on contact are obviously the optimal ways for an antimicrobial surface to function. However, most moist and biologically contaminated areas contain large amounts of material that nonspeciflcally attach to a surface and deactivate it fully. Furthermore, high concentrations of microbes will eventually cover any surface with dead cells, which also deactivate the surface. In the latter case, only surfaces that release biocides will retain their activity. 

Shamby et al. described a surface finish that consists of a water-insoluble composite of silver bromide nanoparticles and poly(4-vinylpyridinium) salts. Again, silver is released and the quarternary ammonium groups kill on contact [139], Gyomard et al. incorporated the natural antimicrobial peptide gramicidin A into a LbL matrix and were able to show, that the peptide kills Enterococcus faecalis in the surroundings when released and on the surface in immobilized form [140], It is also possible that the antimicrobial a-poly-L-lysine in the LbL layer helped a little. 

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