1
|
Wu J, Li X, Kong R, Wang J, Wang X. Analysis of biofilm expansion rate of Bacillus subtilis (MTC871) on agar substrates with different stiffness. Can J Microbiol 2023; 69:479-487. [PMID: 37379574 DOI: 10.1139/cjm-2022-0259] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/30/2023]
Abstract
The surface morphology of mature biofilms is heterogeneous and can be divided into concentric rings wrinkles (I), labyrinthine networks wrinkles (II), radial ridges wrinkles (III), and branches wrinkles (IV), according to surface wrinkle structure and distribution characteristics. Due to the wrinkle structures, channels are formed between the biofilm and substrate and transport nutrients, water, metabolic products, etc. We find that expansion rate variations of biofilms growing on substrates with high and low agar concentrations (1.5, 2.0, 2.5 wt.%) are not in the same phase. In the first 3 days' growth, the interaction stress between biofilm and each agar substrate increases, which makes the biofilm expansion rate decreases before wrinkle pattern IV (branches) comes up. After 3 days, in the later growth stage after wrinkle pattern IV appears, the biofilm has larger expansion rate growing on 2.0 wt.% agar concentration, which has the larger wrinkle distance in wrinkle pattern IV reducing energy consumption. Our study shows that the stiff substrate does not always inhibit the biofilm expansion, although it does in the earlier stage; after that, mature biofilms acquire larger expansion rate by adjusting the growth mode through the wrinkle evolution even in nutrient extremely depletion.
Collapse
Affiliation(s)
- Jin Wu
- School of Mechanical Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Xianyong Li
- School of Mechanical Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Rui Kong
- School of Mechanical Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Jiankun Wang
- School of Mechanical Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Xiaoling Wang
- School of Mechanical Engineering, University of Science and Technology Beijing, Beijing 100083, China
- School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA
| |
Collapse
|
2
|
Lin QW, Lu JQ, Huang YS, Liu JJ, Chen WM, Lin J. Cyclic Diguanylate G-Quadruplex Inducer-Nitric Oxide Donor Conjugate as a Bifunctional Antibiofilm Agent and Antibacterial Synergist against Pseudomonas aeruginosa with a Hyperbiofilm Phenotype. J Med Chem 2023; 66:11927-11939. [PMID: 37606617 DOI: 10.1021/acs.jmedchem.3c00516] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/23/2023]
Abstract
Antibiotic resistance caused by biofilm formation is a clinical challenge. Nitric oxide (NO) can effectively disperse a mature biofilm and can also synergistically influence the level of cyclic diguanylate (c-di-GMP), a universal secondary messenger that plays an important role in biofilm formation in bacteria. Based on our previous finding that c-di-GMP G-quadruplex inducers are effective biofilm formation inhibitors, we designed and synthesized a c-di-GMP G-quadruplex inducer-NO donor conjugate (A11@NO) as a bifunctional antibiofilm agent after obtaining the c-di-GMP G-quadruplex inducer (A11), which has an amino group capable of binding to a nitroso group (NO donor). The conjugate A11@NO showed better biofilm inhibition efficiency than A11, and it can also eradicate mature biofilm. Additionally, it exhibited good antimicrobial synergism against Pseudomonas aeruginosa and helped elevate the bactericidal efficiency of tobramycin against biofilm-formed bacteria. In combination with tobramycin, A11@NO also improved the survival rate of Caenorhabditis elegans in a hyperbiofilm environment.
Collapse
Affiliation(s)
- Qian-Wen Lin
- College of Pharmacy, Jinan University, Guangzhou 511400, China
| | - Jin-Qiang Lu
- The First Affiliated Hospital of Jinan University, Jinan University, Guangzhou 510632, P. R. China
| | - Ye-Si Huang
- College of Pharmacy, Jinan University, Guangzhou 511400, China
| | - Jie-Jiao Liu
- College of Pharmacy, Jinan University, Guangzhou 511400, China
| | - Wei-Min Chen
- College of Pharmacy, Jinan University, Guangzhou 511400, China
| | - Jing Lin
- College of Pharmacy, Jinan University, Guangzhou 511400, China
| |
Collapse
|
3
|
Wang X, Blumenfeld R, Feng XQ, Weitz DA. 'Phase transitions' in bacteria - From structural transitions in free living bacteria to phenotypic transitions in bacteria within biofilms. Phys Life Rev 2022; 43:98-138. [PMID: 36252408 DOI: 10.1016/j.plrev.2022.09.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Accepted: 09/30/2022] [Indexed: 12/05/2022]
Abstract
Phase transitions are common in inanimate systems and have been studied extensively in natural sciences. Less explored are the rich transitions that take place at the micro- and nano-scales in biological systems. In conventional phase transitions, large-scale properties of the media change discontinuously in response to continuous changes in external conditions. Such changes play a significant role in the dynamic behaviours of organisms. In this review, we focus on some transitions in both free-living and biofilms of bacteria. Particular attention is paid to the transitions in the flagellar motors and filaments of free-living bacteria, in cellular gene expression during the biofilm growth, in the biofilm morphology transitions during biofilm expansion, and in the cell motion pattern transitions during the biofilm formation. We analyse the dynamic characteristics and biophysical mechanisms of these phase transition phenomena and point out the parallels between these transitions and conventional phase transitions. We also discuss the applications of some theoretical and numerical methods, established for conventional phase transitions in inanimate systems, in bacterial biofilms.
Collapse
Affiliation(s)
- Xiaoling Wang
- School of Mechanical Engineering, University of Science and Technology Beijing, Beijing 100083, China; John A. Paulson School of Engineering and Applied Sciences, Harvard University, 9 Oxford St, Cambridge, MA, 02138, USA.
| | - Raphael Blumenfeld
- Gonville & Caius College, University of Cambridge, Trinity St., Cambridge CB2 1TA, UK
| | - Xi-Qiao Feng
- Institute of Biomechanics and Medical Engineering, Department of Engineering Mechanics, Tsinghua University, Beijing 100084, China
| | - David A Weitz
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, 9 Oxford St, Cambridge, MA, 02138, USA; Department of Physics, Harvard University, 9 Oxford St, Cambridge, MA, 02138, USA
| |
Collapse
|
4
|
Distributed information encoding and decoding using self-organized spatial patterns. PATTERNS 2022; 3:100590. [PMID: 36277815 PMCID: PMC9583124 DOI: 10.1016/j.patter.2022.100590] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Revised: 07/29/2022] [Accepted: 08/24/2022] [Indexed: 11/28/2022]
Abstract
Dynamical systems often generate distinct outputs according to different initial conditions, and one can infer the corresponding input configuration given an output. This property captures the essence of information encoding and decoding. Here, we demonstrate the use of self-organized patterns that generate high-dimensional outputs, combined with machine learning, to achieve distributed information encoding and decoding. Our approach exploits a critical property of many natural pattern-formation systems: in repeated realizations, each initial configuration generates similar but not identical output patterns due to randomness in the patterning process. However, for sufficiently small randomness, different groups of patterns that arise from different initial configurations can be distinguished from one another. Modulating the pattern-generation and machine learning model training can tune the tradeoff between encoding capacity and security. We further show that this strategy is scalable by implementing the encoding and decoding of all characters of the standard English keyboard. Self-organized patterns can be used for secure information encoding A machine learning-mediated decoding method is proposed Encoding capability and security are tunable through modulating system properties
Self-organized patterns are ubiquitous in biology. They arise from interactions in and between cells, and with the environment. These patterns are often used as a composite phenotype to distinguish cell states and environment conditions. Conceptually, pattern generation under an initial condition is encoding; discerning the initial condition from the pattern represents decoding. Inspired by these examples, we develop a scheme, integrating mathematical modeling and machine learning, to use self-organization for secure and accurate information encoding and decoding. We show that this strategy is applicable to non-biological dynamical systems. We further demonstrate the scalability of the scheme by generating a complete mapping of the standard English keyboard, allowing encoding of English text. Our work serves as an example of nature-inspired computation.
Collapse
|
5
|
Geisel S, Secchi E, Vermant J. The role of surface adhesion on the macroscopic wrinkling of biofilms. eLife 2022; 11:76027. [PMID: 35723588 PMCID: PMC9208754 DOI: 10.7554/elife.76027] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 06/01/2022] [Indexed: 12/14/2022] Open
Abstract
Biofilms, bacterial communities of cells encased by a self-produced matrix, exhibit a variety of three-dimensional structures. Specifically, channel networks formed within the bulk of the biofilm have been identified to play an important role in the colonies' viability by promoting the transport of nutrients and chemicals. Here, we study channel formation and focus on the role of the adhesion of the biofilm matrix to the substrate in Pseudomonas aeruginosa biofilms grown under constant flow in microfluidic channels. We perform phase contrast and confocal laser scanning microscopy to examine the development of the biofilm structure as a function of the substrates' surface energy. The formation of the wrinkles and folds is triggered by a mechanical buckling instability, controlled by biofilm growth rate and the film’s adhesion to the substrate. The three-dimensional folding gives rise to hollow channels that rapidly increase the effective volume occupied by the biofilm and facilitate bacterial movement inside them. The experiments and analysis on mechanical instabilities for the relevant case of a bacterial biofilm grown during flow enable us to predict and control the biofilm morphology.
Collapse
Affiliation(s)
- Steffen Geisel
- Laboratory for Soft Materials, Department of Materials, ETH Zurich, Zurich, Switzerland
| | - Eleonora Secchi
- Department of Civil, Environmental and Geomatic Engineering, ETH Zurich, Zurich, Switzerland
| | - Jan Vermant
- Laboratory for Soft Materials, Department of Materials, ETH Zurich, Zurich, Switzerland
| |
Collapse
|
6
|
Surapaneni VA, Schindler M, Ziege R, de Faria LC, Wölfer J, Bidan CM, Mollen FH, Amini S, Hanna S, Dean MN. Groovy and Gnarly: Surface Wrinkles as a Multifunctional Motif for Terrestrial and Marine Environments. Integr Comp Biol 2022; 62:icac079. [PMID: 35675323 PMCID: PMC9703940 DOI: 10.1093/icb/icac079] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 05/23/2022] [Accepted: 05/24/2022] [Indexed: 12/12/2022] Open
Abstract
From large ventral pleats of humpback whales to nanoscale ridges on flower petals, wrinkled structures are omnipresent, multifunctional, and found at hugely diverse scales. Depending on the particulars of the biological system-its environment, morphology, and mechanical properties-wrinkles may control adhesion, friction, wetting, or drag; promote interfacial exchange; act as flow channels; or contribute to stretching, mechanical integrity, or structural color. Undulations on natural surfaces primarily arise from stress-induced instabilities of surface layers (e.g., buckling) during growth or aging. Variation in the material properties of surface layers and in the magnitude and orientation of intrinsic stresses during growth lead to a variety of wrinkling morphologies and patterns which, in turn, reflect the wide range of biophysical challenges wrinkled surfaces can solve. Therefore, investigating how surface wrinkles vary and are implemented across biological systems is key to understanding their structure-function relationships. In this work, we synthesize the literature in a metadata analysis of surface wrinkling in various terrestrial and marine organisms to review important morphological parameters and classify functional aspects of surface wrinkles in relation to the size and ecology of organisms. Building on our previous and current experimental studies, we explore case studies on nano/micro-scale wrinkles in biofilms, plant surfaces, and basking shark filter structures to compare developmental and structure-vs-function aspects of wrinkles with vastly different size scales and environmental demands. In doing this and by contrasting wrinkle development in soft and hard biological systems, we provide a template of structure-function relationships of biological surface wrinkles and an outlook for functionalized wrinkled biomimetic surfaces.
Collapse
Affiliation(s)
- Venkata A Surapaneni
- City University of Hong Kong, 31 To Yuen Street, Kowloon, Hong Kong
- Max Planck Institute of Colloids and Interfaces, Am Mühlenberg 1, Potsdam, Brandenburg 14476, Germany
| | - Mike Schindler
- City University of Hong Kong, 31 To Yuen Street, Kowloon, Hong Kong
| | - Ricardo Ziege
- Max Planck Institute of Colloids and Interfaces, Am Mühlenberg 1, Potsdam, Brandenburg 14476, Germany
| | | | - Jan Wölfer
- Humboldt University of Berlin, Unter den Linden 6, Berlin 10099, Germany
| | - Cécile M Bidan
- Max Planck Institute of Colloids and Interfaces, Am Mühlenberg 1, Potsdam, Brandenburg 14476, Germany
| | - Frederik H Mollen
- Elasmobranch Research Belgium, Rehaegenstraat 4, 2820 Bonheiden, Belgium
| | - Shahrouz Amini
- Max Planck Institute of Colloids and Interfaces, Am Mühlenberg 1, Potsdam, Brandenburg 14476, Germany
| | - Sean Hanna
- University College London, 14 Upper Woburn Place, London WC1H 0NN, UK
| | - Mason N Dean
- City University of Hong Kong, 31 To Yuen Street, Kowloon, Hong Kong
- Max Planck Institute of Colloids and Interfaces, Am Mühlenberg 1, Potsdam, Brandenburg 14476, Germany
| |
Collapse
|
7
|
Luzala MM, Muanga CK, Kyana J, Safari JB, Zola EN, Mbusa GV, Nuapia YB, Liesse JMI, Nkanga CI, Krause RWM, Balčiūnaitienė A, Memvanga PB. A Critical Review of the Antimicrobial and Antibiofilm Activities of Green-Synthesized Plant-Based Metallic Nanoparticles. NANOMATERIALS (BASEL, SWITZERLAND) 2022; 12:1841. [PMID: 35683697 PMCID: PMC9182092 DOI: 10.3390/nano12111841] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Revised: 04/03/2022] [Accepted: 04/05/2022] [Indexed: 02/01/2023]
Abstract
Metallic nanoparticles (MNPs) produced by green synthesis using plant extracts have attracted huge interest in the scientific community due to their excellent antibacterial, antifungal and antibiofilm activities. To evaluate these pharmacological properties, several methods or protocols have been successfully developed and implemented. Although these protocols were mostly inspired by the guidelines from national and international regulatory bodies, they suffer from a glaring absence of standardization of the experimental conditions. This situation leads to a lack of reproducibility and comparability of data from different study settings. To minimize these problems, guidelines for the antimicrobial and antibiofilm evaluation of MNPs should be developed by specialists in the field. Being aware of the immensity of the workload and the efforts required to achieve this, we set out to undertake a meticulous literature review of different experimental protocols and laboratory conditions used for the antimicrobial and antibiofilm evaluation of MNPs that could be used as a basis for future guidelines. This review also brings together all the discrepancies resulting from the different experimental designs and emphasizes their impact on the biological activities as well as their interpretation. Finally, the paper proposes a general overview that requires extensive experimental investigations to set the stage for the future development of effective antimicrobial MNPs using green synthesis.
Collapse
Affiliation(s)
- Miryam M. Luzala
- Laboratory of Pharmaceutics and Phytopharmaceutical Drug Development, Faculty of Pharmaceutical Sciences, University of Kinshasa, Kinshasa XI B.P. 212, Democratic Republic of the Congo; (M.M.L.); (C.K.M.); (E.N.Z.); (C.I.N.)
| | - Claude K. Muanga
- Laboratory of Pharmaceutics and Phytopharmaceutical Drug Development, Faculty of Pharmaceutical Sciences, University of Kinshasa, Kinshasa XI B.P. 212, Democratic Republic of the Congo; (M.M.L.); (C.K.M.); (E.N.Z.); (C.I.N.)
| | - Joseph Kyana
- Department of Pharmacy, Faculty of Medecine and Pharmacy, University of Kisangani, Kisangani XI B.P. 2012, Democratic Republic of the Congo;
| | - Justin B. Safari
- Department of Pharmacy, Faculty of Pharmaceutical Sciences and Public Health, Official University of Bukavu, Bukavu B.P. 570, Democratic Republic of the Congo;
- Department of Chemistry, Faculty of Science, Rhodes University, P.O. Box 94, Makhana 6140, South Africa
| | - Eunice N. Zola
- Laboratory of Pharmaceutics and Phytopharmaceutical Drug Development, Faculty of Pharmaceutical Sciences, University of Kinshasa, Kinshasa XI B.P. 212, Democratic Republic of the Congo; (M.M.L.); (C.K.M.); (E.N.Z.); (C.I.N.)
| | - Grégoire V. Mbusa
- Centre Universitaire de Référence de Surveillance de la Résistance aux Antimicrobiens (CURS-RAM), Faculty of Pharmaceutical Sciences, University of Kinshasa, Kinshasa XI B.P. 212, Democratic Republic of the Congo; (G.V.M.); (J.-M.I.L.)
- Laboratory of Experimental and Pharmaceutical Microbiology, Faculty of Pharmaceutical Sciences, University of Kinshasa, Kinshasa XI B.P. 212, Democratic Republic of the Congo
| | - Yannick B. Nuapia
- Laboratory of Toxicology, Faculty of Pharmaceutical Sciences, University of Kinshasa, Kinshasa XI B.P. 212, Democratic Republic of the Congo;
| | - Jean-Marie I. Liesse
- Centre Universitaire de Référence de Surveillance de la Résistance aux Antimicrobiens (CURS-RAM), Faculty of Pharmaceutical Sciences, University of Kinshasa, Kinshasa XI B.P. 212, Democratic Republic of the Congo; (G.V.M.); (J.-M.I.L.)
- Laboratory of Experimental and Pharmaceutical Microbiology, Faculty of Pharmaceutical Sciences, University of Kinshasa, Kinshasa XI B.P. 212, Democratic Republic of the Congo
| | - Christian I. Nkanga
- Laboratory of Pharmaceutics and Phytopharmaceutical Drug Development, Faculty of Pharmaceutical Sciences, University of Kinshasa, Kinshasa XI B.P. 212, Democratic Republic of the Congo; (M.M.L.); (C.K.M.); (E.N.Z.); (C.I.N.)
| | - Rui W. M. Krause
- Department of Chemistry, Faculty of Science, Rhodes University, P.O. Box 94, Makhana 6140, South Africa
- Center for Chemico- and Bio-Medicinal Research (CCBR), Faculty of Science, Rhodes University, P.O. Box 94, Makhana 6140, South Africa
| | - Aistė Balčiūnaitienė
- Lithuanian Research Centre for Agriculture and Forestry, Institute of Horticulture, 54333 Babtai, Lithuania;
| | - Patrick B. Memvanga
- Laboratory of Pharmaceutics and Phytopharmaceutical Drug Development, Faculty of Pharmaceutical Sciences, University of Kinshasa, Kinshasa XI B.P. 212, Democratic Republic of the Congo; (M.M.L.); (C.K.M.); (E.N.Z.); (C.I.N.)
- Department of Pharmacy, Faculty of Medecine and Pharmacy, University of Kisangani, Kisangani XI B.P. 2012, Democratic Republic of the Congo;
- Department of Pharmacy, Faculty of Pharmaceutical Sciences and Public Health, Official University of Bukavu, Bukavu B.P. 570, Democratic Republic of the Congo;
- Centre de Recherche et d’Innovation Technologique en Environnement et en Sciences de la Santé (CRITESS), University of Kinshasa, Kinshasa XI B.P. 212, Democratic Republic of the Congo
| |
Collapse
|
8
|
Mechanical limitation of bacterial motility mediated by growing cell chains. Biophys J 2022; 121:2461-2473. [PMID: 35591787 DOI: 10.1016/j.bpj.2022.05.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Revised: 04/20/2022] [Accepted: 05/12/2022] [Indexed: 11/23/2022] Open
Abstract
Contrasting most known bacterial motility mechanisms, a bacterial sliding motility discovered in at least two Gram-positive bacterial families does not depend on designated motors. Instead, the cells maintain end-to-end connections following cell divisions to form long chains and exploit cell growth and division to push the cells forward. To investigate the dynamics of this motility mechanism, we constructed a mechanical model that depicts the interplay of the forces acting on and between the cells comprising the chain. Due to the exponential growth of individual cells, the tips of the chains can, in principle, accelerate to speeds faster than any known single-cell motility mechanism can achieve. However, analysis of the mechanical model shows that the exponential acceleration comes at the cost of an exponential buildup in mechanical stress in the chain, making overly long chains prone to breakage. Additionally, the mechanical model reveals that the dynamics of the chain expansion hinges on a single non-dimensional parameter. Perturbation analysis of the mechanical model further predicts the critical stress leading to chain breakage and its dependence on the non-dimensional parameter. Finally, we developed a simplistic population expansion model that uses the predicted breaking behavior to estimate the physical limit of chain-mediated population expansion. Predictions from the models provide critical insights into how this motility depends on key physical properties of the cell and the substrate. Overall, our models present a generically applicable theoretical framework for cell chain-mediated bacterial sliding motility and provide guidance for future experimental studies on such motility.
Collapse
|
9
|
Fang JY, Chou WL, Lin CF, Sung CT, Alalaiwe A, Yang SC. Facile Biofilm Penetration of Cationic Liposomes Loaded with DNase I/Proteinase K to Eradicate Cutibacterium acnes for Treating Cutaneous and Catheter Infections. Int J Nanomedicine 2021; 16:8121-8138. [PMID: 34938074 PMCID: PMC8687631 DOI: 10.2147/ijn.s335804] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Accepted: 11/24/2021] [Indexed: 12/22/2022] Open
Abstract
Background The biofilm produced by Cutibacterium acnes is a major infection threat for skin and implanted catheters. Nanoparticles provide a new approach to eradicate biofilms. The present study evaluated the capability of cationic liposomes loaded with DNase I (DNS) and proteinase K (PK) to remove preformed C. acnes biofilms. Methods DNS and PK were able to target and disassemble the biofilm by degrading extracellular polymer substances (EPS). Soyaethyl morpholinium ethosulfate (SME) was used to render a positive charge and enhance the antibacterial activity of the liposomes. Results The cationic liposomes containing enzymes yielded monodisperse nanovesicles ranging between 95 and 150 nm. The entrapment efficiency of the enzymes in the liposomes achieved a value of 67–83%. All liposomal formulations suppressed planktonic C. acnes growth at a minimum inhibitory concentration (MIC) equal to the free SME in the solution. The enzyme in the liposomal form inhibited biofilm growth much better than that in the free form, with the dual enzyme-loaded liposomes demonstrating the greatest inhibition of 54% based on a crystal violet assay. The biofilm-related virulence genes PA380 and PA1035 were downregulated by the combined enzymes in the liposomes but not the individual DNS or PK. Scanning electron microscopy (SEM) and confocal microscopy displayed reduced C. acnes aggregates and biofilm thickness by the liposomal system. The liposomes could penetrate through about 85% of the biofilm thickness. The in vitro pig skin permeation also showed a facile delivery of liposomes into the epidermis, deeper skin strata, and hair follicles. The liposomes exhibited potent activity to eliminate C. acnes colonization in mouse skin and catheters in vivo. The colony-forming units (CFUs) in the catheter treated with the liposomes were reduced by 2 logs compared to the untreated control. Conclusion The data suggested a safe application of the enzyme-loaded cationic liposomes as antibacterial and antibiofilm agents.
Collapse
Affiliation(s)
- Jia-You Fang
- Pharmaceutics Laboratory, Graduate Institute of Natural Products, Chang Gung University, Kweishan, Taoyuan, Taiwan.,Research Center for Food and Cosmetic Safety and Research Center for Chinese Herbal Medicine, Chang Gung University of Science and Technology, Kweishan, Taoyuan, Taiwan.,Department of Anesthesiology, Chang Gung Memorial Hospital, Kweishan, Taoyuan, Taiwan
| | - Wei-Ling Chou
- Department of Traditional Chinese Medicine, Chang Gung Memorial Hospital, Keelung, Taiwan
| | - Chwan-Fwu Lin
- Research Center for Food and Cosmetic Safety and Research Center for Chinese Herbal Medicine, Chang Gung University of Science and Technology, Kweishan, Taoyuan, Taiwan.,Department of Anesthesiology, Chang Gung Memorial Hospital, Kweishan, Taoyuan, Taiwan.,Department of Cosmetic Science, Chang Gung University of Science and Technology, Kweishan, Taoyuan, Taiwan
| | - Calvin T Sung
- Department of Dermatology, University of California, Irvine, CA, USA
| | - Ahmed Alalaiwe
- Department of Pharmaceutics, College of Pharmacy, Prince Sattam Bin Abdulaziz University, Al Kharj, Saudi Arabia
| | - Shih-Chun Yang
- Pharmaceutics Laboratory, Graduate Institute of Natural Products, Chang Gung University, Kweishan, Taoyuan, Taiwan.,Department of Cosmetic Science, Providence University, Taichung, Taiwan
| |
Collapse
|
10
|
Ziege R, Tsirigoni AM, Large B, Serra DO, Blank KG, Hengge R, Fratzl P, Bidan CM. Adaptation of Escherichia coli Biofilm Growth, Morphology, and Mechanical Properties to Substrate Water Content. ACS Biomater Sci Eng 2021; 7:5315-5325. [PMID: 34672512 PMCID: PMC8579398 DOI: 10.1021/acsbiomaterials.1c00927] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
![]()
Biofilms are complex
living materials that form as bacteria become
embedded in a matrix of self-produced protein and polysaccharide fibers.
In addition to their traditional association with chronic infections
or clogging of pipelines, biofilms currently gain interest as a potential
source of functional material. On nutritive hydrogels, micron-sized Escherichia coli cells can build centimeter-large biofilms.
During this process, bacterial proliferation, matrix production, and
water uptake introduce mechanical stresses in the biofilm that are
released through the formation of macroscopic delaminated buckles
in the third dimension. To clarify how substrate water content could
be used to tune biofilm material properties, we quantified E. coli biofilm growth, delamination dynamics, and rigidity
as a function of water content of the nutritive substrates. Time-lapse
microscopy and computational image analysis revealed that softer substrates
with high water content promote biofilm spreading kinetics, while
stiffer substrates with low water content promote biofilm delamination.
The delaminated buckles observed on biofilm cross sections appeared
more bent on substrates with high water content, while they tended
to be more vertical on substrates with low water content. Both wet
and dry biomass, accumulated over 4 days of culture, were larger in
biofilms cultured on substrates with high water content, despite extra
porosity within the matrix layer. Finally, microindentation analysis
revealed that substrates with low water content supported the formation
of stiffer biofilms. This study shows that E. coli biofilms respond to substrate water content, which might be used
for tuning their material properties in view of further applications.
Collapse
Affiliation(s)
- Ricardo Ziege
- Max Planck Institute of Colloids and Interfaces, 14476 Potsdam, Germany
| | | | - Bastien Large
- Max Planck Institute of Colloids and Interfaces, 14476 Potsdam, Germany
| | - Diego O Serra
- Institut für Biologie/Mikrobiologie, Humboldt-Universität zu Berlin, 10115 Berlin, Germany.,Institute of Molecular and Cell Biology, 2000 Rosario, Argentina
| | - Kerstin G Blank
- Max Planck Institute of Colloids and Interfaces, 14476 Potsdam, Germany
| | - Regine Hengge
- Institut für Biologie/Mikrobiologie, Humboldt-Universität zu Berlin, 10115 Berlin, Germany
| | - Peter Fratzl
- Max Planck Institute of Colloids and Interfaces, 14476 Potsdam, Germany
| | - Cécile M Bidan
- Max Planck Institute of Colloids and Interfaces, 14476 Potsdam, Germany
| |
Collapse
|
11
|
Xuan TF, Wang ZQ, Liu J, Yu HT, Lin QW, Chen WM, Lin J. Design and Synthesis of Novel c-di-GMP G-Quadruplex Inducers as Bacterial Biofilm Inhibitors. J Med Chem 2021; 64:11074-11089. [PMID: 34323486 DOI: 10.1021/acs.jmedchem.1c00465] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The formation of biofilms by clinical pathogens typically leads to chronic and recurring antibiotic-resistant infections. High cellular levels of cyclic diguanylate (c-di-GMP), a ubiquitous secondary messenger of bacteria, have been proven to be associated with a sessile biofilm lifestyle of pathogens. A promising antibiofilm strategy involving the induction of c-di-GMP to form dysfunctional G-quadruplexes, thereby blocking the c-di-GMP-mediated biofilm regulatory pathway, was proposed in this study. In this new strategy, a series of novel c-di-GMP G-quadruplex inducers were designed and synthesized for development of therapeutic biofilm inhibitors. Compound 5h exhibited favorable c-di-GMP G-quadruplex-inducing activity and 62.18 ± 6.76% biofilm inhibitory activity at 1.25 μM without any DNA intercalation effect. Moreover, the favorable performance of 5h in interfering with c-di-GMP-related biological functions, including bacterial motility and bacterial extracellular polysaccharide secretion, combined with the reporter strain and transcriptome analysis results confirmed the c-di-GMP signaling-related action mechanism of 5h.
Collapse
Affiliation(s)
- Teng-Fei Xuan
- College of Pharmacy, Jinan University, Guangzhou 510632, P. R. China
| | - Zi-Qiang Wang
- College of Pharmacy, Jinan University, Guangzhou 510632, P. R. China
| | - Jun Liu
- College of Pharmacy, Jinan University, Guangzhou 510632, P. R. China
| | - Hai-Tao Yu
- College of Pharmacy, Jinan University, Guangzhou 510632, P. R. China
| | - Qian-Wen Lin
- College of Pharmacy, Jinan University, Guangzhou 510632, P. R. China
| | - Wei-Min Chen
- College of Pharmacy, Jinan University, Guangzhou 510632, P. R. China
| | - Jing Lin
- College of Pharmacy, Jinan University, Guangzhou 510632, P. R. China
| |
Collapse
|
12
|
Breid D, Lai V, Flowers AT, Guan X, Liu Q, Velankar SS. Drop Spreading and Confinement in Swelling-Driven Folding of Thin Films. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:6985-6994. [PMID: 34080875 DOI: 10.1021/acs.langmuir.1c00520] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Surface instabilities are a versatile method for generating three-dimensional (3D) surface microstructure. When an elastomeric film weakly bonded to a substrate is swollen with solvent, buckle delamination and subsequent sliding of the film on the substrate lead to the formation of tall, self-contacting, and permanent folds. This paper explores the mechanics of fold development when such folding is induced by placing a drop on the surface of the film. We show that capillary effects can induce a strong coupling between folding and drop spreading: as folds develop, they wick the solvent toward the periphery of the drop, further propagating radially aligned folds. Accordingly, a solvent drop spreads far more on films that are weakly adhered to the substrate. As drop size reduces and folding becomes increasingly confined, debonding propagates along the perimeter of the wetted region, thus leading to corral-shaped fold patterns. On the other hand, as drop size increases and confinement effects weaken, isotropically oriented folds appear at a spacing that reduces as swelling increases. The spacing between the folds and the size of the corrals are both determined by the extent to which a single fold relieves compressive stress in its vicinity by sliding. We develop a model for folding which explicitly accounts for the fact that folds must initiate with near-zero volume under the buckle. The model shows that folds can appear even at very low swelling if there are large pre-existing debonded regions at the film-substrate interface.
Collapse
Affiliation(s)
- Derek Breid
- Department of Engineering, Saint Vincent College, Latrobe, Pennsylvania 15650, United States
| | | | | | | | | | | |
Collapse
|
13
|
González-Henríquez CM, Rodriguez-Umanzor FE, Almagro-Correa J, Sarabia-Vallejos MA, Martínez-Campos E, Esteban-Lucía M, Del Campo-García A, Rodríguez-Hernández J. Biocompatible fluorinated wrinkled hydrogel films with antimicrobial activity. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2020; 114:111031. [PMID: 32993990 DOI: 10.1016/j.msec.2020.111031] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Revised: 03/13/2020] [Accepted: 04/27/2020] [Indexed: 12/21/2022]
Abstract
Surface-modified hydrogel films were designed to control the bacterial colonization on their surface and to promote cell proliferation through the gradual insertion of highly hydrophobic functional monomers. These hydrogel films were deposited via spin-coating technique, using muscovite mica as a substrate. These samples were then exposed to different external stimuli to produce wrinkled patterns. The relationship between the monomers which compose the hydrogel, was varied to alter the hydrophobic/hydrophilic balance of the final composite. Contact angle and confocal Raman spectroscopy measurements were carried out to characterize the surface and the bulk of the hydrogel film. Cell proliferation and antimicrobial tests were performed using premyoblastic murine cells (C2C12-GFP) and RAW 264.7 (ATCC® TIB-71) macrophagic cell lines, and also for bacteria strains, Staphylococcus aureus and Escherichia coli. The results indicate that the inclusion of the TFPMA produces an increase in cell proliferation, together with a decrease in living bacterial colonies after 48 h, both for Gram-positive or Gram-negative species.
Collapse
Affiliation(s)
- Carmen M González-Henríquez
- Facultad de Ciencias Naturales, Matemáticas y del Medio Ambiente, Departamento de Química, Universidad Tecnológica Metropolitana, P.O. Box 9845, Correo 21, Santiago, Chile; Programa Institucional de Fomento a la Investigación, Desarrollo e Innovación, Universidad Tecnológica Metropolitana, Ignacio Valdivieso 2409, Santiago, Chile.
| | - Fernando E Rodriguez-Umanzor
- Facultad de Ciencias Naturales, Matemáticas y del Medio Ambiente, Departamento de Química, Universidad Tecnológica Metropolitana, P.O. Box 9845, Correo 21, Santiago, Chile
| | - Jessica Almagro-Correa
- Facultad de Ciencias Naturales, Matemáticas y del Medio Ambiente, Departamento de Química, Universidad Tecnológica Metropolitana, P.O. Box 9845, Correo 21, Santiago, Chile
| | - Mauricio A Sarabia-Vallejos
- Departamento de Ingeniería Estructural y Geotecnia, Escuela de Ingeniería, Pontificia Universidad Católica de Chile, P.O. Box 306, Correo 22, Santiago, Chile; Instituto de Ingeniería Biológica y Medica, Escuela de Ingeniería, Pontificia Universidad Católica de Chile, P.O. Box 306, Correo 22, Santiago, Chile
| | - Enrique Martínez-Campos
- Tissue Engineering Group, Instituto de Estudios Biofuncionales, Universidad Complutense de Madrid, Associated Unit to the ICTP-CSIC Polymer Functionalization Group, Paseo Juan XXIII, n° 1, 28040 Madrid, Spain
| | - Miguel Esteban-Lucía
- Tissue Engineering Group, Instituto de Estudios Biofuncionales, Universidad Complutense de Madrid, Associated Unit to the ICTP-CSIC Polymer Functionalization Group, Paseo Juan XXIII, n° 1, 28040 Madrid, Spain
| | | | - Juan Rodríguez-Hernández
- Polymer Functionalization Group, Instituto de Ciencia y Tecnología de Polímeros-Consejo Superior de Investigaciones Científicas (ICTP-CSIC), Departamento de Química Macromolecular Aplicada, Juan de la Cierva 3, 28006 Madrid, Spain
| |
Collapse
|
14
|
WANG XIAOLING, TAN YIFAN, LIU JIALI, HU SHUAISHUAI, ZHAO HUI. THE EVOLVING WRINKLE PATTERN OF THE BACILLUS SUBTILIS BIOFILM PROVIDING MORE LIVING SPACE FOR CELLS. J MECH MED BIOL 2020. [DOI: 10.1142/s0219519420500487] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The biofilm wrinkle evolution is the growth mechanism by which bacteria regulate their physiological state in response to the environmental change. We use the parameter of surface complexity to describe different wrinkle patterns. The surface complexity is defined that the biofilm surface area contact with the air is divided by the projected area of the biofilm. We find that the biofilm surface complexity variation is positively proportional to the number of spores. Although each wrinkle pattern has various wrinkle thickness and width, surface complexities of some patterns are almost same, which guarantees cells have enough living space. Through the observation of the growth of the damaged biofilm, we further find that the biofilm expansion along the circumferential direction is faster than that along radial direction, which means that the internal stress along the circumferential direction contributes the wrinkle formation. Our work provides a new perspective to study biofilm morphologies, and relates the morphology evolution with phenotypes in the Bacillus subtilis biofilm.
Collapse
Affiliation(s)
- XIAOLING WANG
- School of Mechanical Engineering, University of Science and Technology Beijing, Beijing 100083, P. R. China
- School of Engineering and Applied Sciences, Harvard University Cambridge, MA 02138, USA
| | - YIFAN TAN
- School of Mechanical Engineering, University of Science and Technology Beijing, Beijing 100083, P. R. China
| | - JIALI LIU
- School of Mechanical Engineering, University of Science and Technology Beijing, Beijing 100083, P. R. China
| | - SHUAISHUAI HU
- School of Mechanical Engineering, University of Science and Technology Beijing, Beijing 100083, P. R. China
| | - HUI ZHAO
- State Key Laboratory of Computer Science, Institute of Software, Chinese Academy of Sciences, Beijing 100190, P. R. China
| |
Collapse
|
15
|
Nonuniform growth and surface friction determine bacterial biofilm morphology on soft substrates. Proc Natl Acad Sci U S A 2020; 117:7622-7632. [PMID: 32193350 DOI: 10.1073/pnas.1919607117] [Citation(s) in RCA: 61] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
During development, organisms acquire three-dimensional (3D) shapes with important physiological consequences. While basic mechanisms underlying morphogenesis are known in eukaryotes, it is often difficult to manipulate them in vivo. To circumvent this issue, here we present a study of developing Vibrio cholerae biofilms grown on agar substrates in which the spatiotemporal morphological patterns were altered by varying the agar concentration. Expanding biofilms are initially flat but later undergo a mechanical instability and become wrinkled. To gain mechanistic insights into this dynamic pattern-formation process, we developed a model that considers diffusion of nutrients and their uptake by bacteria, bacterial growth/biofilm matrix production, mechanical deformation of both the biofilm and the substrate, and the friction between them. Our model shows quantitative agreement with experimental measurements of biofilm expansion dynamics, and it accurately predicts two distinct spatiotemporal patterns observed in the experiments-the wrinkles initially appear either in the peripheral region and propagate inward (soft substrate/low friction) or in the central region and propagate outward (stiff substrate/high friction). Our results, which establish that nonuniform growth and friction are fundamental determinants of stress anisotropy and hence biofilm morphology, are broadly applicable to bacterial biofilms with similar morphologies and also provide insight into how other bacterial biofilms form distinct wrinkle patterns. We discuss the implications of forming undulated biofilm morphologies, which may enhance the availability of nutrients and signaling molecules and serve as a "bet hedging" strategy.
Collapse
|
16
|
Galdino RV, Benevides CA, Tenório RP. Diffusion maps of Bacillus subtilis biofilms via magnetic resonance imaging highlight a complex network of channels. Colloids Surf B Biointerfaces 2020; 190:110905. [PMID: 32143011 DOI: 10.1016/j.colsurfb.2020.110905] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Revised: 02/20/2020] [Accepted: 02/24/2020] [Indexed: 10/24/2022]
Abstract
Bacillus subtilis microorganism when cultivated under chemically-defined conditions developed a biofilm with an unusual pattern of wrinkles on the surface. Some questions were raised about whether there was a special function of these wrinkles for the biofilm itself, since they resembled microchannels that could be involved in the transport of nutrients within the biofilm. Since the diffusion is the main mechanism for nutrient transport to biofilm from the medium, the role of these wrinkled structures in the whole diffusion within the biofilm was investigated using diffusion-weighted magnetic resonance imaging (DW-MRI). Data from these diffusion images was used to generate 2D diffusion maps which highlighted the striking channel features of the biofilm surface. The diffusion maps revealed a network of interconnected channels, with self-diffusion coefficients higher in the microchannels than in other regions of the biofilms. Polar plots made from 2D diffusion maps obtained from the plane of the biofilm show an anisotropy of the diffusion inside the microchannels, with the diffusion higher when along the principal direction of the microchannels. These results agree with the model, that the buckling of the biofilm surface from the B. subtilis creates microchannels that can enhance diffusion throughout the biofilm.
Collapse
Affiliation(s)
- Ramon V Galdino
- Centro Regional de Ciências Nucleares do Nordeste, Comissão Nacional de Energia Nuclear, Av. Prof. Luiz Freire, 200, Cidade Universitária, 50740-545 Recife, Pernambuco, Brazil; Agência Pernambucana de Vigilância Sanitária, Secretaria Estadual de Saúde de Pernambuco, Praça Osvaldo Cruz, s/n, Boa Vista, 50050-210 Recife, Pernambuco, Brazil
| | - Clayton A Benevides
- Centro Regional de Ciências Nucleares do Nordeste, Comissão Nacional de Energia Nuclear, Av. Prof. Luiz Freire, 200, Cidade Universitária, 50740-545 Recife, Pernambuco, Brazil
| | - Rômulo P Tenório
- Centro Regional de Ciências Nucleares do Nordeste, Comissão Nacional de Energia Nuclear, Av. Prof. Luiz Freire, 200, Cidade Universitária, 50740-545 Recife, Pernambuco, Brazil.
| |
Collapse
|
17
|
Luminescent Nanosensors for Ratiometric Monitoring of Three-Dimensional Oxygen Gradients in Laboratory and Clinical Pseudomonas aeruginosa Biofilms. Appl Environ Microbiol 2019; 85:AEM.01116-19. [PMID: 31420335 DOI: 10.1128/aem.01116-19] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Accepted: 08/09/2019] [Indexed: 01/08/2023] Open
Abstract
Bacterial biofilms can form persistent infections on wounds and implanted medical devices and are associated with many chronic diseases, such as cystic fibrosis. These infections are medically difficult to treat, as biofilms are more resistant to antibiotic attack than their planktonic counterparts. An understanding of the spatial and temporal variation in the metabolism of biofilms is a critical component toward improved biofilm treatments. To this end, we developed oxygen-sensitive luminescent nanosensors to measure three-dimensional (3D) oxygen gradients, an application of which is demonstrated here with Pseudomonas aeruginosa biofilms. The method was applied here and improves on traditional one-dimensional (1D) methods of measuring oxygen profiles by investigating the spatial and temporal variation of oxygen concentration when biofilms are challenged with antibiotic attack. We observed an increased oxygenation of biofilms that was consistent with cell death from comparisons with antibiotic kill curves for PAO1. Due to the spatial and temporal nature of our approach, we also identified spatial and temporal inhomogeneities in the biofilm metabolism that are consistent with previous observations. Clinical strains of P. aeruginosa subjected to similar interrogation showed variations in resistance to colistin and tobramycin, which are two antibiotics commonly used to treat P. aeruginosa infections in cystic fibrosis patients.IMPORTANCE Biofilm infections are more difficult to treat than planktonic infections for a variety of reasons, such as decreased antibiotic penetration. Their complex structure makes biofilms challenging to study without disruption. To address this limitation, we developed and demonstrated oxygen-sensitive luminescent nanosensors that can be incorporated into biofilms for studying oxygen penetration, distribution, and antibiotic efficacy-demonstrated here with our sensors monitoring antibiotic impacts on metabolism in biofilms formed from clinical isolates. The significance of our research is in demonstrating not only a nondisruptive method for imaging and measuring oxygen in biofilms but also that this nanoparticle-based sensing platform can be modified to measure many different ions and small molecule analytes.
Collapse
|
18
|
Yan J, Fei C, Mao S, Moreau A, Wingreen NS, Košmrlj A, Stone HA, Bassler BL. Mechanical instability and interfacial energy drive biofilm morphogenesis. eLife 2019; 8:43920. [PMID: 30848725 PMCID: PMC6453567 DOI: 10.7554/elife.43920] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Accepted: 03/06/2019] [Indexed: 11/17/2022] Open
Abstract
Surface-attached bacterial communities called biofilms display a diversity of morphologies. Although structural and regulatory components required for biofilm formation are known, it is not understood how these essential constituents promote biofilm surface morphology. Here, using Vibrio cholerae as our model system, we combine mechanical measurements, theory and simulation, quantitative image analyses, surface energy characterizations, and mutagenesis to show that mechanical instabilities, including wrinkling and delamination, underlie the morphogenesis program of growing biofilms. We also identify interfacial energy as a key driving force for mechanomorphogenesis because it dictates the generation of new and the annihilation of existing interfaces. Finally, we discover feedback between mechanomorphogenesis and biofilm expansion, which shapes the overall biofilm contour. The morphogenesis principles that we discover in bacterial biofilms, which rely on mechanical instabilities and interfacial energies, should be generally applicable to morphogenesis processes in tissues in higher organisms. Engineers have long studied how mechanical instabilities cause patterns to form in inanimate materials, and recently more attention has been given to how such forces affect biological systems. For example, stresses can build up within a tissue if one layer grows faster than an adjacent layer. The tissue can release this stress by wrinkling, folding or creasing. Though ancient and single-celled, bacteria can also develop spectacular patterns when they exist in the lifestyle known as a biofilm: a community of cells adhered to a surface. But do mechanical instabilities drive the patterns seen in biofilms? To investigate, Yan, Fei, Mao et al. grew biofilms of the bacterium called Vibrio cholerae – which causes the disease cholera – on solid, non-growing ‘substrates’. This work revealed that as the biofilms grow, their expansion is constrained by the substrate, and this situation generates mechanical stresses. To release the stresses, the biofilm initially folds to form wrinkles. Later, as the biofilm expands further, small parts of it detach from the substrate to form blisters. The same forces that keep water droplets spherical (known as interfacial forces) dictate how the blisters evolve, interact, and eventually shape the expanding biofilm. Using these principles, Yan et al. could engineer the biofilm into desired shapes. Collectively, the results presented by Yan et al. connect the shape of the biofilm surface with its material properties, in particular its stiffness. Understanding this relationship could help researchers to develop new ways to remove harmful biofilms, such as those that cause disease or that damage underwater structures. The stiffness of biofilms is already known to affect how well bacteria can resist antibiotics. Future studies could look for new genes or compounds that change the material properties of a biofilm, thereby altering the biofilm surface.
Collapse
Affiliation(s)
- Jing Yan
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, United States.,Department of Molecular Biology, Princeton University, Princeton, United States
| | - Chenyi Fei
- Department of Molecular Biology, Princeton University, Princeton, United States
| | - Sheng Mao
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, United States
| | - Alexis Moreau
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, United States
| | - Ned S Wingreen
- Department of Molecular Biology, Princeton University, Princeton, United States
| | - Andrej Košmrlj
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, United States
| | - Howard A Stone
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, United States
| | - Bonnie L Bassler
- Department of Molecular Biology, Princeton University, Princeton, United States.,The Howard Hughes Medical Institute, Chevy Chase, United States
| |
Collapse
|
19
|
Oshri O, Liu Y, Aizenberg J, Balazs AC. Delamination of a thin sheet from a soft adhesive Winkler substrate. Phys Rev E 2018; 97:062803. [PMID: 30011476 DOI: 10.1103/physreve.97.062803] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Indexed: 11/07/2022]
Abstract
A uniaxially compressed thin elastic sheet that is resting on a soft adhesive substrate can form a blister, which is a small delaminated region, if the adhesion energy is sufficiently weak. To analyze the equilibrium behavior of this system, we model the substrate as a Winkler or fluid foundation. We develop a complete set of equations for the profile of the sheet at different applied pressures. We show that at the edge of delamination, the height of the sheet is equal to sqrt[2]ℓ_{c}, where ℓ_{c} is the capillary length. We then derive an approximate solution to these equations and utilize them for two applications. First, we determine the phase diagram of the system by analyzing possible transitions from the flat and wrinkled to delaminated states of the sheet. Second, we show that our solution for a blister on a soft foundation converges to the known solution for a blister on a rigid substrate that assumed a discontinuous bending moment at the blister edges. This continuous convergence into a discontinuous state marks the formation of a boundary layer around the point of delamination. The width of this layer relative to the extent length of the blister, ℓ, scales as w/ℓ∼(ℓ_{c}/ℓ_{ec})^{1/2}, where ℓ_{ec} is the elastocapillary length scale. Notably, our findings can provide guidelines for utilizing compression to remove thin biofilms from surfaces and thereby prevent the fouling of the system.
Collapse
Affiliation(s)
- Oz Oshri
- Chemical Engineering Department, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, USA
| | - Ya Liu
- Chemical Engineering Department, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, USA
| | - Joanna Aizenberg
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA.,Wyss Institute for Biologically Inspired Engineering and Kavli Institute for Bionano Science and Technology, Harvard University, Cambridge, Massachusetts 02138, USA.,Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Anna C Balazs
- Chemical Engineering Department, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, USA
| |
Collapse
|