Model-Driven Controlled Alteration of Nanopillar Cap Architecture Reveals its Effects on Bactericidal Activity.

Taiyeb Zahir,Jiri Pesek,Herman Ramon,Jan Michiels,Ashish Rathore,Maarten Fauvart,Sabine Franke,Jasper Van Pee,Xiumei Xu,Bart Smeets

doi:10.3390/microorganisms8020186

Abstract

Nanostructured surfaces can be engineered to kill bacteria in a contact-dependent manner. The study of bacterial interactions with a nanoscale topology is thus crucial to developing antibacterial surfaces. Here, a systematic study of the effects of nanoscale topology on bactericidal activity is presented. We describe the antibacterial properties of highly ordered and uniformly arrayed cotton swab-shaped (or mushroom-shaped) nanopillars. These nanostructured surfaces show bactericidal activity against Staphylococcus aureus and Pseudomonas aeruginosa. A biophysical model of the cell envelope in contact with the surface, developed ab initio from the infinitesimal strain theory, suggests that bacterial adhesion and subsequent lysis are highly influenced by the bending rigidity of the cell envelope and the surface topography formed by the nanopillars. We used the biophysical model to analyse the influence of the nanopillar cap geometry on the bactericidal activity and made several geometrical alterations of the nanostructured surface. Measurement of the bactericidal activities of these surfaces confirms model predictions, highlights the non-trivial role of cell envelope bending rigidity, and sheds light on the effects of nanopillar cap architecture on the interactions with the bacterial envelope. More importantly, our results show that the surface nanotopology can be rationally designed to enhance the bactericidal efficiency.

Highlights

The development of nanostructured surfaces that can prevent bacterial colonization and biofilm formation is an active subject of research [1,2]
The deposition of silicon dioxide on these nanopillars resulted in an overhang profile that looked like cotton swabs or mushrooms (Figure 1c)
When bacteria adhere to a surface with such a topography, the cell envelope is non-uniformly stretched over the gaps, which in turn leads to an increase in the local tension [11]

Summary

Introduction

The development of nanostructured surfaces that can prevent bacterial colonization and biofilm formation is an active subject of research [1,2]. These surfaces have enormous potential for applications in healthcare and industry, promising to limit the spread of infectious diseases [3,4,5]. Ivanova et al found that nanopillars on cicada wings can lyse bacterial cells upon contact [7] This discovery was followed by the development of silicon [8], titanium [9], and polymer-based [10] antibacterial surfaces with similar topographies. When bacteria adhere to these nanospikes, the stretching and subsequent rupture of the cell envelope suspended between the nanospikes causes cell lysis [11]

Methods

Results

Conclusion