Impact of Nanoscale Topography on Genomics and Proteomics of Adherent Bacteria

Abstract

Bacterial adhesion onto inorganic/nanoengineered surfaces is a key issue in biotechnology and medicine, because it is one of the first necessary steps to determine a general pathogenic event. Understanding the molecular mechanisms of bacteria-surface interaction represents a milestone for planning a new generation of devices with unanimously certified antibacterial characteristics. Here, we show how highly controlled nanostructured substrates impact the bacterial behavior in terms of morphological, genomic, and proteomic response. We observed by atomic force microscopy (AFM) and scanning electron microscopy (SEM) that type-1 fimbriae typically disappear in Escherichia coli adherent onto nanostructured substrates, as opposed to bacteria onto reference glass or flat gold surfaces. A genetic variation of the fimbrial operon regulation was consistently identified by real time qPCR in bacteria interacting with the nanorough substrates. To gain a deeper insight into the molecular basis of the interaction mechanisms, we explored the entire proteomic profile of E. coli by 2D-DIGE, finding significant changes in the bacteria adherent onto the nanorough substrates, such as regulations of proteins involved in stress processes and defense mechanisms. We thus demonstrated that a pure physical stimulus, that is, a nanoscale variation of surface topography, may play per se a significant role in determining the morphological, genetic, and proteomic profile of bacteria. These data suggest that in depth investigations of the molecular processes of microorganisms adhering to surfaces are of great importance for the design of innovative biomaterials with active biological functionalities.

Antibacterial properties and toxicity from metallic nanomaterials

“…73 Therefore, fabrication of gold nanorods (AuNRs) where manipulation of size, dimension, and aspect ratio is possible is imperative in the advancement of applications such as drug delivery and water treatment. Zhu et al 74 prepared two-and three-dimensional uniform arrays of AuNRs by confined convective arraying techniques and studied the photoheated bacterial effects on E. coli.…”

Effect of Micro- and Nanoscale Topography on the Adhesion of Bacterial Cells to Solid Surfaces

“…Additionally, the appendages were thicker for cells attached to the nonporous substrates than for those present on the porous substrates. In a study by Rizzello et al (27), E. coli cells exposed to gold substrates with nanoscale topography did not express certain type-1 fimbriae, in contrast to cells exposed to smooth gold and glass surfaces. A comprehensive analysis of the E. coli proteome showed that, in addition to fimbria expression, genes involved in stress response and defense mechanisms were expressed differently in cells exposed to nanorough and nanosmooth surfaces.…”

Nano and Microscale Topographies for the Prevention of Bacterial Surface Fouling

“…Mechanisms underpinning attachment to nanoscale topographies for mammalian cells is a greatly studied area which has continued to foster significant findings and major contributions to the wealth of knowledge on eukaryotic cell behavior [82][83][84][85]. However, as Hsu et al [48] have described, attachment phenomena for bacterial cells at the nanoscale is less understood, as relatively few reported works have explored the effects of nanoscale topography on bacterial attachment behavior and biofilm formation [23,49,54,86,87]. In fact, some work on bacterial attachment to nanoscale topography resulted in a higher degree of attachment to nanoscaled surfaces rather than planar or micron-scaled topography [88][89][90][91].…”

“…Thus, in the presence of topographical features, they are not easily deformed (as mammalian cells would typically be) [7]. Instead, bacterial appendages are both small and relatively flexible, enabling them to probe nanoscale features [54,86,87]. Thus, these extracellular appendages could play a crucial role in attachment to surface features much smaller than the dimensions of the cells themselves.…”