The use of atomic force microscopy for studying interactions of bacterial biofilms with surfaces

Beech, Iwona B.; Smith, James R.; Steele, A.; Penegar, Ian; Campbell, S. A.

doi:10.1016/s0927-7765(01)00233-8

Cited by 139 publications

(74 citation statements)

References 64 publications

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“…Highermagnification AFM images revealed a granular structure for the observed EPS (inset in Fig. 1D and E), in agreement with previous work on Pseudomonas putida and Pseudomonas aeruginosa biofilms (7,12,36). While the dimensions of the grains ranged from approximately 5 to 40 nm, as determined by their height, the measured widths were larger (approximately hundreds of nanometers) due to tip convolution.…”

Section: Resultssupporting

confidence: 90%

Nanoscale Structural and Mechanical Properties of Nontypeable Haemophilus influenzae Biofilms

et al. 2009

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Nontypeable Haemophilus influenzae (NTHI) bacteria are commensals in the human nasopharynx, as well as pathogens associated with a spectrum of acute and chronic infections. Two important factors that influence NTHI pathogenicity are their ability to adhere to human tissue and their ability to form biofilms. Extracellular polymeric substances (EPS) and bacterial appendages such as pili critically influence cell adhesion and intercellular cohesion during biofilm formation. Structural components in the outer cell membrane, such as lipopolysaccharides, also play a fundamental role in infection of the host organism. In spite of their importance, these pathogenic factors are not yet well characterized at the nanoscale. Here, atomic force microscopy (AFM) was used in aqueous environments to visualize structural details, including probable Hif-type pili, of live NTHI bacteria at the early stages of biofilm formation. Using single-molecule AFM-based spectroscopy, the molecular elasticities of lipooligosaccharides present on NTHI cell surfaces were analyzed and compared between two strains (PittEE and PittGG) with very different pathogenicity profiles. Furthermore, the stiffness of single cells of both strains was measured and subsequently their turgor pressure was estimated.

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Section: Resultssupporting

confidence: 90%

Nanoscale Structural and Mechanical Properties of Nontypeable Haemophilus influenzae Biofilms

et al. 2009

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“…Biocompatibility of implants and formation of biofilms on surfaces (films made up of cells, having in part different properties from isolated cells) [948] are closely related to this issue. In aqueous solutions, surface charges on cell and substrates surface are expected to contribute to the adhesion process, either promoting adhesion in the case of opposite charges or acting as a barrier due to electric double-layer repulsion (Section 6.1).…”

Section: Cell and Animal Adhesionmentioning

confidence: 99%

Force measurements with the atomic force microscope: Technique, interpretation and applications

Butt

Cappella

Kappl

2005

Surface Science Reports

3,246

2,949

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“…Drying is expected to significantly change the strength and overall character of a biofilm; therefore, measurements made on dry biofilm must be interpreted and applied carefully. A few AFM studies have investigated biofilm properties, such as interaction and attachment to surfaces under aqueous conditions (5,21). Yet, there is a real need to expand this work to study additional properties of whole biofilms under aqueous conditions.…”

mentioning

confidence: 99%

Biofilm Cohesiveness Measurement Using a Novel Atomic Force Microscopy Methodology

Ahimou¹,

Semmens²,

Novak³

et al. 2007

Appl Environ Microbiol

117

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Biofilms can be undesirable, as in those covering medical implants, and beneficial, such as when they are used for waste treatment. Because cohesive strength is a primary factor affecting the balance between growth and detachment, its quantification is essential in understanding, predicting, and modeling biofilm development. In this study, we developed a novel atomic force microscopy (AFM) method for reproducibly measuring, in situ, the cohesive energy levels of moist 1-day biofilms. The biofilm was grown from an undefined mixed culture taken from activated sludge. The volume of biofilm displaced and the corresponding frictional energy dissipated were determined as a function of biofilm depth, resulting in the calculation of the cohesive energy. Our results showed that cohesive energy increased with biofilm depth, from 0.10 ؎ 0.07 nJ/m 3 to 2.05 ؎ 0.62 nJ/m 3 . This observation was reproducible, with four different biofilms showing the same behavior. Cohesive energy also increased from 0.10 ؎ 0.07 nJ/m 3 to 1.98 ؎ 0.34 nJ/m 3 when calcium (10 mM) was added to the reactor during biofilm cultivation. These results agree with previous reports on calcium increasing the cohesiveness of biofilms. This AFM-based technique can be performed with available off-the-shelf instrumentation. It could therefore be widely used to examine biofilm cohesion under a variety of conditions.It is essential to understand biofilm stability to both encourage biofilm maintenance in some applications, such as waste treatment, and effectively remove undesired biofilm in others, as in biofilms covering medical implants. Biofilm detachment is one of the critical factors that balance growth and plays a role in the development of biofilm spatial heterogeneity. While factors responsible for biofilm growth are well studied (16,29,39,42,43), those controlling the detachment process are not clearly understood (28,36,38). As a consequence, a good understanding of the relationships between operating conditions and biofilm cohesion is lacking. The cohesive strength of the biofilm is influenced by extracellular polymeric substances (EPS) and specific compounds, such as calcium, which fill the space between microbial cells and bind cells together (23,30). Understanding the cohesive interactions in the biofilm matrix under a variety of conditions could lead to the design of new strategies for controlling biofilm development based on disrupting or protecting the matrix holding the biofilm together.Because cohesive strength is a primary factor affecting biofilm sloughing, its quantification is essential in understanding detachment. A few methods based on the use of custom devices have been proposed to investigate biofilm cohesive strength. Poppele and Hozalski (31) measured the tensile strength levels of biofilms from activated sludge by using a micromechanical device based on the deflection of a glass micropipette separating a microbial aggregate held by suction. Körstgens et al. (22) used a uniaxial compression measurement device to determine the yield st...

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The use of atomic force microscopy for studying interactions of bacterial biofilms with surfaces

Cited by 139 publications

References 64 publications

Nanoscale Structural and Mechanical Properties of Nontypeable Haemophilus influenzae Biofilms

Nanoscale Structural and Mechanical Properties of Nontypeable Haemophilus influenzae Biofilms

Force measurements with the atomic force microscope: Technique, interpretation and applications

Biofilm Cohesiveness Measurement Using a Novel Atomic Force Microscopy Methodology

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