Submicrometer-Sized Roughness Suppresses Bacteria Adhesion

Abstract

Biofilm formation is most commonly combatted with antibiotics or biocides. However, proven toxicity and increasing resistance of bacteria increase the need for alternative strategies to prevent adhesion of bacteria to surfaces. Chemical modification of the surfaces by tethering of functional polymer brushes or films provides a route toward antifouling coatings. Furthermore, nanorough or superhydrophobic surfaces can delay biofilm formation. Here we show that submicrometer-sized roughness can outweigh surface chemistry by testing the adhesion of E. coli to surfaces of different topography and wettability over long exposure times (>7 days). Gram-negative and positive bacterial strains are tested for comparison. We show that an irregular three-dimensional layer of silicone nanofilaments suppresses bacterial adhesion, both in the presence and absence of an air cushion. We hypothesize that a 3D topography can delay biofilm formation (i) if bacteria do not fit into the pores of the coating or (ii) if bending of the bacteria is required to adhere. Thus, such a 3D topography offers an underestimated possibility to design antibacterial surfaces that do not require biocides or antibiotics.

Potential of Superhydrophobic Surface for Blood-Contacting Medical Devices

“…The presence of local curvature by the protrusions reduces the anchoring points for bacteria cells. On the other hand, the spacing between the structured surface smaller than the size of bacteria cells has a strong likelihood to prevent anchoring of the bacteria [ 71 ].…”

Superhydrophobic Nanocoatings as Intervention against Biofilm-Associated Bacterial Infections

“…The superhydrophobicity of a surface can be modulated by its surface charge and roughness, in which they play a significant role in determining the ability of microbial cells to adhere to surfaces of medical implants in the early stages of biofilm formation [ 122 ]. Generally, a rough surface reduces the contact area and adhesion force between microbial cells and the surface due to the presence of surface protrusions that facilitate air trapping within the surface structure as observed in the Cassie–Baxter wetting regime, thereby contributing to a high contact angle, low sliding angle, and self-cleaning property, which are the characteristic features of a superhydrophobic surface [ 122 , 123 ]. In addition, the local curvatures on the surface protrusions also effectively reduce the anchoring points for microbial cells [ 123 ].…”

“…Generally, a rough surface reduces the contact area and adhesion force between microbial cells and the surface due to the presence of surface protrusions that facilitate air trapping within the surface structure as observed in the Cassie–Baxter wetting regime, thereby contributing to a high contact angle, low sliding angle, and self-cleaning property, which are the characteristic features of a superhydrophobic surface [ 122 , 123 ]. In addition, the local curvatures on the surface protrusions also effectively reduce the anchoring points for microbial cells [ 123 ]. One study by Wu et al had demonstrated that micro- and nano-topographies of rough surfaces can influence the adhesion of bacteria and the subsequent formation of early biofilm.…”

Quantitative determination of rapid biomass formation on pyro-electrified polymer sheets

“…Therefore, the evaluation of microbial capability to form biofilms is a critical issue for assessing how different environmental factors may affect their viability [ 4 ]. The process of bacterial adhesion leading to the biofilm formation is subjected to physical, chemical and biological phenomena, such as the interaction with specific topographic structures [ 5 , 6 ] or with specific pH and adhesive properties [ 7 ]. The biofilm develops in different steps including a first physical interaction that is reversible and, successively, through irreversible processes at molecular and cellular level [ [8] , [9] , [10] ].…”