Selective antibiofilm properties and biocompatibility of nano-ZnO and nano-ZnO/Ag coated surfaces

Abstract

Spread of pathogenic microbes and antibiotic-resistant bacteria in health-care settings and public spaces is a serious public health challenge. Materials and surface-treatments that prevent solid surface colonization and biofilm formation or impede touch-transfer of viable microbes could provide means to decrease pathogen transfer from high-touch surfaces in critical applications. Both, ZnO and Ag nanoparticles have shown a great potential in antimicrobial applications. Although antimicrobial properties of such nanoparticle suspensions and their biocompatibility with human cells are well studied, less is known about nano-enabled solid surfaces. Here we demonstrate that surfaces coated with nano-ZnO or nano-ZnO/Ag composites possess species-selective medium-dependent antibiofilm activity against Escherichia coli, Staphylococcus aureus and Candida albicans. Colonization of nano-ZnO surfaces by E. coli and S. aureus was decreased in oligotrophic (nutrient-poor, no growth) conditions with E. coli showinghigher sensitivity to Ag and S. aureus to Zn, respectively. Minor to no effect was observed for bacteria in growth medium (nutrient-rich, exponential growth). Inversely, compared to uncoated surfaces, nano-ZnO surfaces enhanced biofilm formation by C. albicans in oligotrophic conditions and just a minor transient negative effect was seen in nutrient-rich medium. However, enhanced C. albicans biofilm formation on nano-ZnO surfaces was effectively counteracted by the addition of Ag. Our results not only showed that nano-ZnO/Ag coated solid surfaces have the potential to effectively decrease surface colonization by the bacteria E. coli and S. aureus but also indicated the importance of the use of application-appropriate test conditions and exposure medium in antimicrobial surface testing. Possible selective enhancement of biofilm formation by the yeast C. albicans on Zn-enabled surfaces should be taken into account in antimicrobial surface development.

Plant-Based Bimetallic Silver-Zinc Oxide Nanoparticles: A Comprehensive Perspective of Synthesis, Biomedical Applications, and Future Trends

“…This significant knowledge could reveal the performance of nanoparticles in contact conditions. Productive results in these areas usually require a deep vision into the fundamentals of the mechanical properties of bimetallic nanoparticles, for example, movement law, interfacial adhesion, hardness, elastic modulus, size-dependent characteristics, and friction [ 73 ].…”