Reduced bacterial colonisation on surfaces coated with silicone nanostructures

Bacterial adhesion on silicone nano- and microstructures is investigated in stagnant and flow experiments. Static adhesion tests are performed in 0.9% NaCl solution. These experiments reveal that the number of Staphylococcus epidermidis (S. epidermidis) and Escherichia coli (E. coli) adhering to glass surfaces can significantly be reduced if silicone nanofilament and rod coatings are present. Further, flow experiments are conducted in a parallel-plate flow chamber using 0.9% NaCl solution and artificial urine as medium. Silicone nanofilament coated surfaces are compared to uncoated glass surfaces. E. coli colonisation on filament coated surfaces is reduced for at least 24 h in 0.9% NaCl solution, while in artificial urine no reduction is observed after 24 h. S. epidermidis shows converse adhesion behaviour. Here, initial adhesion on nanofilaments is promoted but the number of adherent S. epidermidis seems to decrease after extended contact time. The obtained results demonstrate that superhydrophobic silicone surfaces significantly reduce bacterial colonisation under stagnant and dynamic conditions. However, the bacterial adhesion behaviour depends on the architecture of the silicone nano- and microstructures and the bacterial species investigated.