Alginate exopolymer significantly modulates the viscoelastic properties and resilience of bacterial biofilms

Abstract Biofilms are viscoelastic gels with a cross-linked network of biopolymers forming an extracellular matrix that protects bacteria from most antimicrobial treatments. This study examines the physical role of the matrix in preventing recolonisation using a mucoid Pseudomonas aeruginosa (P. aer...

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Main Authors: Binu Kundukad, Scott A. Rice, Patrick S. Doyle, Staffan Kjelleberg
Format: Article
Language:English
Published: Nature Portfolio 2025-06-01
Series:npj Biofilms and Microbiomes
Online Access:https://doi.org/10.1038/s41522-025-00718-6
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author Binu Kundukad
Scott A. Rice
Patrick S. Doyle
Staffan Kjelleberg
author_facet Binu Kundukad
Scott A. Rice
Patrick S. Doyle
Staffan Kjelleberg
author_sort Binu Kundukad
collection DOAJ
description Abstract Biofilms are viscoelastic gels with a cross-linked network of biopolymers forming an extracellular matrix that protects bacteria from most antimicrobial treatments. This study examines the physical role of the matrix in preventing recolonisation using a mucoid Pseudomonas aeruginosa (P. aeruginosa ΔmucA) and isogenic wild-type Pseudomonas aeruginosa PAO1. We investigated the recolonisation of pre-formed live biofilms and the residual matrix left behind after bacterial eradication with N-acetyl cysteine (NAC). P. aeruginosa ΔmucA, which overproduces alginate, prevented recolonisation through swelling and increased elastic modulus. In contrast, the wild-type P. aeruginosa biofilm matrix exhibited minimal swelling and decreased elasticity, suggesting crosslink breakage. These observations align with polymer physics theories where alginate’s polyelectrolyte nature drives swelling through the Donnan effect, enhancing matrix stability. Meanwhile, the Psl-rich wild-type matrix limited swelling but showed reduced mechanical stability. This study underscores the critical role of matrix composition in biofilm mechanics, influencing bacterial protection regardless of viability.
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institution Kabale University
issn 2055-5008
language English
publishDate 2025-06-01
publisher Nature Portfolio
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series npj Biofilms and Microbiomes
spelling doaj-art-e3dbdfb8e3a24e99b464154ad8325ab02025-08-20T03:45:11ZengNature Portfolionpj Biofilms and Microbiomes2055-50082025-06-0111111010.1038/s41522-025-00718-6Alginate exopolymer significantly modulates the viscoelastic properties and resilience of bacterial biofilmsBinu Kundukad0Scott A. Rice1Patrick S. Doyle2Staffan Kjelleberg3Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological UniversityCSIRO, Microbiomes for One Systems Health, Agriculture and FoodSingapore MIT Alliance for Research and TechnologySingapore Centre for Environmental Life Sciences Engineering, Nanyang Technological UniversityAbstract Biofilms are viscoelastic gels with a cross-linked network of biopolymers forming an extracellular matrix that protects bacteria from most antimicrobial treatments. This study examines the physical role of the matrix in preventing recolonisation using a mucoid Pseudomonas aeruginosa (P. aeruginosa ΔmucA) and isogenic wild-type Pseudomonas aeruginosa PAO1. We investigated the recolonisation of pre-formed live biofilms and the residual matrix left behind after bacterial eradication with N-acetyl cysteine (NAC). P. aeruginosa ΔmucA, which overproduces alginate, prevented recolonisation through swelling and increased elastic modulus. In contrast, the wild-type P. aeruginosa biofilm matrix exhibited minimal swelling and decreased elasticity, suggesting crosslink breakage. These observations align with polymer physics theories where alginate’s polyelectrolyte nature drives swelling through the Donnan effect, enhancing matrix stability. Meanwhile, the Psl-rich wild-type matrix limited swelling but showed reduced mechanical stability. This study underscores the critical role of matrix composition in biofilm mechanics, influencing bacterial protection regardless of viability.https://doi.org/10.1038/s41522-025-00718-6
spellingShingle Binu Kundukad
Scott A. Rice
Patrick S. Doyle
Staffan Kjelleberg
Alginate exopolymer significantly modulates the viscoelastic properties and resilience of bacterial biofilms
npj Biofilms and Microbiomes
title Alginate exopolymer significantly modulates the viscoelastic properties and resilience of bacterial biofilms
title_full Alginate exopolymer significantly modulates the viscoelastic properties and resilience of bacterial biofilms
title_fullStr Alginate exopolymer significantly modulates the viscoelastic properties and resilience of bacterial biofilms
title_full_unstemmed Alginate exopolymer significantly modulates the viscoelastic properties and resilience of bacterial biofilms
title_short Alginate exopolymer significantly modulates the viscoelastic properties and resilience of bacterial biofilms
title_sort alginate exopolymer significantly modulates the viscoelastic properties and resilience of bacterial biofilms
url https://doi.org/10.1038/s41522-025-00718-6
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AT patricksdoyle alginateexopolymersignificantlymodulatestheviscoelasticpropertiesandresilienceofbacterialbiofilms
AT staffankjelleberg alginateexopolymersignificantlymodulatestheviscoelasticpropertiesandresilienceofbacterialbiofilms