Mechanical signatures of microbial biofilms in micropillar-embedded growth chambers

Abstract

Biofilms are surface-attached communities of microorganisms embedded in an extracellular matrix and are essential for the cycling of organic matter in natural and engineered environments. They are also the leading cause of many infections, for example, those associated with chronic wounds and implanted medical devices. The extracellular matrix is a key biofilm component that determines its architecture and defines its physical properties. Herein, we used growth chambers embedded with micropillars to study the net mechanical forces (differential pressure) exerted during biofilm formation in situ. Pressure from the biofilm is transferred to the micropillars via the extracellular matrix, and reduction of major matrix components decreases the magnitude of micropillar deflections. The spatial arrangement of micropillar deflections caused by pressure differences in the different biofilm strains may potentially be used as mechanical signatures for biofilm characterization. Hence, we submit that micropillar-embedded growth chambers provide insights into the mechanical properties and dynamics of the biofilm and its matrix.

The role of surface adhesion on the macroscopic wrinkling of biofilms

“…These values give a critical stress of needed for the biofilm to buckle away from the substrate. Previous experimental studies have reported that P. aeruginosa biofilms are indeed capable of exerting stresses in the kPa-range during growth ( Chew et al, 2016 ).…”

Towards standardized mechanical characterization of microbial biofilms: analysis and critical review

“…Mechanical properties can serve as quantitative criteria against which performance can be measured. Release of biocides or silver from surface coatings, micropillars 74 , 75 or bioinspired nanostructural topography 76 are some examples of strategies used in low adhesion surfaces. The control of topographical and physio-chemical properties of the substratum such as roughness, charge, tension, and hydrophobicity, stiffness 77 may offer insights for developing surfaces that inhibit biofilm formation.…”

Recent advances in studying single bacteria and biofilm mechanics

“…Multicellular biofilm clusters have also been directly grown in chambers embedded with flexible micropillars where they may generate high enough forces (or "differential pressures") onto micropillars to deflect them [137]. Considering all the different studied bacterial strains, the authors reported differential pressure values ranging from 1 to 25 kPa.…”