Assessing the impact of silicon nanowires on bacterial transformation and viability of Escherichia coli

We investigated the biomaterial interface between the bacteria Escherichia coli DH5 alpha and silicon nanowire patterned surfaces. We optimised the engineering of silicon nanowire coated surfaces using metal-assisted chemical etching. Using a combination of focussed ion beam scanning electron microscopy, and cell viability and transformation assays, we found that with increasing interfacing force, cell viability decreases, as a result of increasing cell rupture. However, despite this aggressive interfacing regime, a proportion of the bacterial cell population remains viable. We found that the silicon nanowires neither resulted in complete loss of cell viability nor partial membrane disruption and corresponding DNA plasmid transformation. Critically, assay choice was observed to be important, as a reduction-based metabolic reagent was found to yield false-positive results on the silicon nanowire substrate. We discuss the implications of these results for the future design and assessment of bacteria-nanostructure interfacing experiments.

Automated summary

The study optimized the engineering of silicon nanowire coated surfaces through chemical etching, and found that increasing interfacing force led to decreased cell viability of Escherichia coli. However, a proportion of the bacterial cell population remained viable despite the aggressive interfacing regime. The silicon nanowires did not result in complete loss of cell viability or partial membrane disruption and corresponding DNA plasmid transformation.