Controlling Geometry and Flow Through Bacterial Bridges on Patterned Lubricant‐Infused Surfaces (pLIS)

Abstract

Gram-negative bacteria such as Acinetobacter spp., Pseudomonas aeruginosa (P. aeruginosa), Escherichia coli (E. coli), Enterobacter spp. are widely spread in natural and artificial environments. [1] The facultative pathogenic P. aeruginosa is a major cause of chronic infections strongly involved in cystic fibrosis patients Spatial control of bacteria and biofilms on surfaces is necessary to understand the biofilm formation and the social interactions between bacterial communities, which could provide useful hints to study the biofilm-involved diseases. Here patterned lubricant-infused surfaces (pLIS) are utilized to fabricate connective structures named "bacterial bridges" between bacterial colonies of Pseudomonas aeruginosa by a simple dewetting method. It is demonstrated that the bacteria attached to hydrophilic areas and bacteria precipitated on lubricant infused borders both contribute to the formation of bacterial bridges. The geometry and distribution of bridges can be controlled using predesigned superhydrophobic-hydrophilic patterns. It is demonstrated that bacterial bridges connecting bacteria colonies act as bio-microfluidic channels and can transport liquids, nutrients, and antibacterial substances between neighboring bacteria clusters. Thus, bacterial bridges can be used to study formation, spreading, and development of bacterial colonies, and communication within and between isolated biofilms. and immunocompromised individuals. [2] Various mechanisms including active efflux of antibiotics, cell wall barrier, enzymatic inactivation of drugs, and/or antibiotic target changes/protection contribute to the antibiotic resistance of Gram-negative bacteria. [3] Except for its high level of intrinsic resistance, Gram-negative bacteria such as P. aeruginosa are able to achieve adaptive antibiotic resistance by living together as biofilms. [4] Bridge or string-like structures of bacteria colonies were reported in biofilm studies previously. Thus, Jahed et al. used micropatterened poly(dimethyl siloxane) (PDMS) to form 3D nanostring of microcolonies of Staphyloccocus aureus. [5] Drescher et al. demonstrated that P. aeruginosa flowing through microfluidic channels made from PDMS formed streamer structures resembling biofilm bridges, causing clogging. [6] In our previous study, we used patterned liquid-infused surfaces (pLIS) to form arrays of homogeneous biofilm microclusters and observed string-like connections formed between such biofilm patches. [7] Since the string-like structure is observed under highly controlled conditions, it indicates that this phenomenon might be common in nature. The phenomenon of bacterial bridges could help better understand biofilms, complex 3D biofilms structure, function, or factors that can affect biofilm formation, and the removal of biofilms. It is not clear, how far micro-structures contribute to formation and adaptation of biofilms. Bioinspired LIS have been introduced as an antifouling material. [8] The solid porous surface of LIS provides its mechanical stability and also s...

Water in bacterial biofilms: pores and channels, storage and transport functions

“…A similar minimal width of 100 nm was reported in order to avoid adsorption of antimicrobials to channel walls upon diffusion-controlled penetration of an antimicrobial in an infectious biofilm (Ju et al 2020). However, intra-colony channels with much larger diameters of around 10 mm have also been described in E. coli, using giant objective lens microscopy with a high numerical aperture at low magnification ("mesoscopy") (Rooney et al 2020) and even wider channels (18-99 mm) have been described in P. aeruginosa (Lei et al 2020). Collectively, it can thus be concluded that biofilm channels effective for transport processes must have a minimal width of around 100 nm.…”

“…This corresponds with visualised channel lengths in V. cholerae (Fern andez-Delgado et al 2016), S. mutans (Galbiatti de Carvalho et al 2012), B. subtilis (Wilking et al 2013) and phototrophic (Phoenix and Holmes 2008) biofilms and three species biofilms of P. aeruginosa, Pseudomonas fluorescens and Klebsiella pneumoniae biofilm (De Beer and Stoodley 1995;Stewart 2012). In biofilms of P. aeruginosa, channels have been described with a length of around 700 mm, bridging the distance between two places in a biofilm, but these channels had an extremely wide range of widths (Lei et al 2020). Accepting a minimal length of 1 lm and a width of 100 nm as a characteristic of a channel, channels can be distinguished from pores by a length/width ratio > 10, while pores should have a length to width ratio closer to one.…”

A microfluidic approach for studying microcolonization of Escherichia coli O157:H7 on leaf trichome‐mimicking surfaces under fluid shear stress

“…Under this flow, stick-slip dynamics explains the microscopic receding line wherein the contact line remains pinned, as in a "stick" mode, at a specific point on the micropost before detaching into slip mode to move to the next micropost (Yang et al, 2018). Here, the filamentous hornlike structures at the top layer of micropost would be a result of stuck the dimensions, directions, numbers, and positions of bridges (Drescher et al, 2013;Jahed et al, 2017;Lei et al, 2019;Lei et al, 2020;Rusconi et al, 2010;Valiei et al, 2012). shear on E. coli O157:H7 microcolonization using wild-type and isogenic mutant E. coli O157:H7 strains lacking adhesin and adherencemeditating components, or new platforms simulating more complicated but more realistic leaf surfaces (i.e., surface patterns, mechanical properties, and chemical compositions).…”

“…As such, leafy green-mimicking substrates have been applied as platforms for a mechanistic understanding of the biofilm formations of various types of cells and a demonstration of the distinguishing plant surface characteristics, including superhydrophobicity and self-cleaning properties. Furthermore, characterization of extracellular matrix from biofilm and their development to filamentous structures, referred to biofilm streamers, have been demonstrated using various approaches including surface modification (i.e., topographical and chemical modifications), flow conditions, bacterial strains, and nutrition availability (Drescher et al, 2013;Jahed et al, 2017;Lei et al, 2019Lei et al, , 2020Rusconi et al, 2010;Valiei et al, 2012). While the interactions between biofilm structures and fluid flow are important, there is still little information regarding the emergence of microcolonies in growing biofilms which may potentially lead to cross-contamination events on fresh produce.…”

High‐Resolution Patterned Functionalization of Slippery “Liquid‐Like” Brush Surfaces via Microdroplet‐Confined Growth of Multifunctional Polydopamine Arrays

“…For example, micropatterned hydrophilic patches on hydrophobic or slippery surfaces could be employed as biomimetic water-harvesting materials from fog. [21][22][23] The patterned surfaces with defined surface properties also enabled the manipulation of arrays of microdroplets or cells for high-throughput studies, [24][25][26][27] as well as the control on directional transport of droplets to work as surface-tension-confined microfluidic devices without the need for microchannels. [28][29][30] In addition, patterning of surface wettability or chemical reactivity are essential in various sensor systems based on biomolecular immobilization, photonic crystals, or plasmonic nanostructures, in which the assembly of molecules or nanoparticles could be selectively guided into desired positions by the micropatterns.…”