ABSTRACT
Spread of pathogenic microbes and antibiotic-resistant bacteria in health-care settings and public spaces is a serious public health challenge. Materials that prevent solid surface colonization or impede touch-transfer of viable microbes could provide means to decrease pathogen transfer from high-touch surfaces in critical applications. ZnO and Ag nanoparticles have shown great potential in antimicrobial applications. Less is known about nano-enabled surfaces. Here we demonstrate that surfaces coated with nano-ZnO or nano-ZnO/Ag composites are not cytotoxic to human keratinocytes and possess species-selective medium-dependent antibiofilm activity against Escherichia coli, Staphylococcus aureus and Candida albicans. Colonization of nano-ZnO and nano-ZnO/Ag surfaces by E. coli and S. aureus was decreased in static oligotrophic conditions (no planktonic growth). Moderate to no effect was observed for bacterial biofilms in growth medium (supporting exponential growth). Inversely, nano-ZnO surfaces enhanced biofilm formation by C. albicans in oligotrophic conditions. However, enhanced C. albicans biofilm formation on nano-ZnO surfaces was effectively counteracted by the addition of Ag. Possible selective enhancement of biofilm formation by the yeast C. albicans on Zn-enabled surfaces should be taken into account in antimicrobial surface development. Our results also indicated the importance of the use of application-appropriate test conditions and exposure medium in antimicrobial surface testing.
Subject(s)
Biofilms/drug effects , Silver/pharmacology , Zinc Oxide/pharmacology , Anti-Bacterial Agents , Anti-Infective Agents , Bacteria/drug effects , Bacteria/growth & development , Biofilms/growth & development , Candida albicans/growth & development , Escherichia coli/growth & development , Metal Nanoparticles/therapeutic use , Microbial Sensitivity Tests , Nanocomposites/therapeutic use , Silver/metabolism , Staphylococcus aureus/growth & development , Zinc Oxide/metabolismABSTRACT
We have developed a new lithographically-based patterning process which significantly increases the throughput of experiments which probe how repair proteins scan DNA molecules for errors. In this process, nanoscale barriers are formed to interrupt the flow of a lipid bilayer in which DNA is tethered to proteins in the bilayer. The barriers trap the DNA, which is then stretched out by hydrodynamic flow, resulting in the formation of "DNA curtains." Nanoimprint lithography is used to facilitate massively parallel data collection for protein diffusion experiments on DNA.
