Critical Review of Nanopillar-Based Mechanobactericidal Systems

The rise of multidrug resistant bacteria is the biggest threat to human health globally as described by the World Health Organization (WHO). Mechano-bactericidal surfaces provides a sustainable approach to address this concern by eradicating pathogens, especially bacteria, “right-at-the-point” of first contacting the surface. However, the lack of a “design to manufacture” approach due to our limited understanding of the mechano-bactericidal mechanism has impeded engineering optimization to develop scalable exploitation routes in various healthcare applications. It can be argued that the reason, most particularly, is the limitations and uncertainties associated with the current instrumentation and simulation capabilities which has led to several streams of test protocols. This review highlights the current understanding on the mechano-bactericidal mechanisms in light of the contributing factors and various techniques which are used to postulate these mechanisms. The review offers a critique on the variations observed on how nanostructured surfaces found in literature have been evaluated such that the test protocols and the outcomes are incomparable. The review also shows a strong need of developing more accurate models of a bacterium as the currently reported experimental data is insufficient to develop bacteria’s material models (constitutive equations). The review also alludes to the scarcity of direct experimental evidence of the mechano-bactericidal mechanism suggesting a strong need for further in-situ monitoring as a future research direction.