A Selection of Platforms to Evaluate Surface Adhesion and Biofilm Formation in Controlled Hydrodynamic Conditions

Abstract

The early colonization of surfaces and subsequent biofilm development have severe impacts in environmental, industrial, and biomedical settings since they entail high costs and health risks. To develop more effective biofilm control strategies, there is a need to obtain laboratory biofilms that resemble those found in natural or man-made settings. Since microbial adhesion and biofilm formation are strongly affected by hydrodynamics, the knowledge of flow characteristics in different marine, food processing, and medical device locations is essential. Once the hydrodynamic conditions are known, platforms for cell adhesion and biofilm formation should be selected and operated, in order to obtain reproducible biofilms that mimic those found in target scenarios. This review focuses on the most widely used platforms that enable the study of initial microbial adhesion and biofilm formation under controlled hydrodynamic conditions - modified Robbins devices, flow chambers, rotating biofilm devices, microplates, and microfluidic devices - and where numerical simulations have been used to define relevant flow characteristics, namely the shear stress and shear rate.

Formation, Development, and Cross-Species Interactions in Biofilms

“…In addition, modeling biofilm formation in vitro allows the biofilm to be studied more closely and helps us to explore potential treatments for the targeted biofilms. For instance, flow chambers are promising approaches that could be used to assess bacterial adhesion to biomaterial surfaces, which is evaluated by microscopy ( Gomes and Mergulhão, 2021 ). Microfluidic platforms contain multiple channels to study bacterial adhesion, biofilm formation, or antimicrobial treatments.…”

Dynamic Salmonella Enteritidis biofilms development under different flow conditions and their removal using nanoencapsulated thymol

“…However, it should be pointed out that a reverse trend of biofilms formation could be observed with increased flow rates exceeding the highest flow rate tested. Higher flow rates could be accompanied by even more hydrodynamic forces that can slough of biofilms from the substratum or can lead to a non-attachment of biofilms due to the high shear forces imposed that could be above the critical levels for biofilms attachment [ 9 , [34] , [35] , [36] ].

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Biofilm Formation of Helicobacter pylori in Both Static and Microfluidic Conditions Is Associated With Resistance to Clarithromycin

“…For this reason, this step of experiments was associated with the methodology validation. In the first stage, we were faced with the task of selecting a functional model from the two classically used in studies of biofilm formation under microfluidic conditions (Gomes and Mergulhão, 2021): (1) a constant flow of medium containing bacteria and a measurement of the ability to adhere and form biofilm under a constant shear force pressure, or (2) a continuous flow of medium without bacteria and a measurement of the ability to grow biofilm only from pre-adhered cells/ microaggregates. It turned out that only the first model provided suitable growth of the tested H. pylori strains (see further stages of the experiments), while for all the six tested H. pylori strains in the second model we did not observe any biomass increase (example H. pylori M172: Supplementary Video 1).…”