scholarly journals Determination of the Shear Force at the Balance between Bacterial Attachment and Detachment in Weak-Adherence Systems, Using a Flow Displacement Chamber

2007 ◽  
Vol 74 (3) ◽  
pp. 916-919 ◽  
Author(s):  
M. Reza Nejadnik ◽  
Henny C. van der Mei ◽  
Henk J. Busscher ◽  
Willem Norde
Keyword(s):  
Bacterial Adhesion ◽  
Biofilm Formation ◽  
Shear Force ◽  
Polymer Brush ◽  
Bacterial Attachment ◽  
Adhesion Forces ◽  
Shear Forces ◽  
Flow Displacement

ABSTRACT We introduce a procedure for determining shear forces at the balance between attachment and detachment of bacteria under flow. This procedure can be applied to derive adhesion forces in weak-adherence systems, such as polymer brush coatings, which are currently at the center of attention for their control of bacterial adhesion and biofilm formation.

scholarly journals Initial Bacterial Adhesion and Biofilm Formation on Aligner Materials

Antibiotics ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 908
Author(s):  
Sibel Tektas ◽  
Thomas Thurnheer ◽  
Theodore Eliades ◽  
Thomas Attin ◽  
Lamprini Karygianni
Keyword(s):  
Bacterial Adhesion ◽  
Biofilm Formation ◽  
Statistical Significance ◽  
Sample Surface ◽  
Human Saliva ◽  
Bacterial Attachment ◽  
Columbia Blood Agar ◽  
Conventional Brackets ◽  
Aerobic And Anaerobic

The present study aims to assess the initial bacterial adhesion and biofilm formation on different aligner materials. A total of four different aligner materials, CA-medium (CAM), copolyester (COP), Duran (DUR), Erkodur (ERK), were tested. Stimulated human saliva was obtained from six healthy volunteers. Salivary bacteria were harvested by centrifugation, and 1 mL of the salivary suspension was injected onto each sample surface for 2 h and 3 days, respectively. The samples were then washed twice with 5 mL 0.9% NaCl solution, and non-adherent bacteria were removed. The adherent microorganisms were dislodged from the sample surfaces after ultrasonication for 4 min in 1 mL 0.9% NaCl on ice. After the incubation of the adherent salivary bacteria under both aerobic and anaerobic conditions on Columbia blood agar plates at 37 °C and 5% CO2 and in anaerobic jars overnight, several dilutions thereof were used for the determination of CFUs. This protocol was applied three times, obtaining an average of nine independent measurements for each material group. Overall, the differences between the tested aligner materials as well as between the materials and controls were not of statistical significance (p > 0.05). Regarding initial bacterial attachment and biofilm formation, the tested aligner materials are comparable to enamel and metal orthodontic brackets and can be therefore considered for clinical use. The four tested aligner materials CAM, COP, DUR, ERK showed no significant differences in initial microbial attachment and biofilm formation of aerobic and anaerobic species compared to enamel and conventional brackets.

scholarly journals Bond Strengthening in Oral Bacterial Adhesion to Salivary Conditioning Films

2008 ◽  
Vol 74 (17) ◽  
pp. 5511-5515 ◽  
Author(s):  
Henny C. van der Mei ◽  
Minie Rustema-Abbing ◽  
Joop de Vries ◽  
Henk J. Busscher
Keyword(s):  
Bacterial Adhesion ◽  
Biofilm Formation ◽  
Specific Interactions ◽  
Adhesion Forces ◽  
Bacterial Strains ◽  
Bacterial Interactions ◽  
Initial Adhesion ◽  
Conditioning Film ◽  
Interacting Surfaces ◽  
Conditioning Films

ABSTRACT Transition from reversible to irreversible bacterial adhesion is a highly relevant but poorly understood step in initial biofilm formation. We hypothesize that in oral biofilm formation, irreversible adhesion is caused by bond strengthening due to specific bacterial interactions with salivary conditioning films. Here, we compared the initial adhesion of six oral bacterial strains to salivary conditioning films with their adhesion to a bovine serum albumin (BSA) coating and related their adhesion to the strengthening of the binding forces measured with bacteria-coated atomic force microscopy cantilevers. All strains adhered in higher numbers to salivary conditioning films than to BSA coatings, and specific bacterial interactions with salivary conditioning films were accompanied by stronger initial adhesion forces. Bond strengthening occurred on a time scale of several tens of seconds and was slower for actinomyces than for streptococci. Nonspecific interactions between bacteria and BSA coatings strengthened twofold faster than their specific interactions with salivary conditioning films, likely because specific interactions require a closer approach of interacting surfaces with the removal of interfacial water and a more extensive rearrangement of surface structures. After bond strengthening, bacterial adhesion forces with a salivary conditioning film remained stronger than those with BSA coatings.

Sliding Friction between Polymer-brush-bearing Surfaces: Crossover from Brush-brush Interfacial Shear to Polymer-substrate Slip.

2000 ◽  
Vol 651 ◽  
Author(s):  
Jacob Klein
Keyword(s):  
Polymer Brushes ◽  
Shear Force ◽  
Reasonable Agreement ◽  
Sliding Friction ◽  
Polymer Brush ◽  
Interfacial Shear ◽  
Force Response ◽  
Shear Forces ◽  
Stick Slip ◽  
Frictional Forces

AbstractA model is presented for the shear (or frictional) forces Fs between two surfaces a distance D apart as they slide past each other while bearing mutually compressed polymer brushes, on the assumption that sliding takes place at the brush-brush interface. The predictions of the model for the rapid increase in Fs at increasing compressions are in reasonable agreement with experiments on polystyrene brushes immersed in toluene over two decades in Fs. At higher compressions (smaller D) the experimental shear forces increase only slowly, and diverge from the calculated ones which continue to increase rapidly; at the same time the form of the shear force response at these higher compressions reverts from a viscous-like one to a stick-slip behaviour. These observations strongly indicate that at sufficiently high compressions the plane of slip crosses over from the brush-brush interface to the polymer-solid surface.

scholarly journals Strategies for Antimicrobial Peptides Immobilization on Surfaces to Prevent Biofilm Growth on Biomedical Devices

Antibiotics ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 13
Author(s):  
Mathieu Nicolas ◽  
Bruno Beito ◽  
Marta Oliveira ◽  
Maria Tudela Martins ◽  
Bruno Gallas ◽  
...  
Keyword(s):  
Antimicrobial Peptides ◽  
Surface Functionalization ◽  
Bacterial Adhesion ◽  
Biofilm Formation ◽  
Biomedical Applications ◽  
Mechanisms Of Action ◽  
Bacterial Attachment ◽  
Biofilm Growth ◽  
Synthetic Routes ◽  
Immobilization Techniques

Nosocomial and medical device-induced biofilm infections affect millions of lives and urgently require innovative preventive approaches. These pathologies have led to the development of numerous antimicrobial strategies, an emergent topic involving both natural and synthetic routes, among which some are currently under testing for clinical approval and use. Antimicrobial peptides (AMPs) are ideal candidates for this fight. Therefore, the strategies involving surface functionalization with AMPs to prevent bacterial attachment/biofilms formation have experienced a tremendous development over the last decade. In this review, we describe the different mechanisms of action by which AMPs prevent bacterial adhesion and/or biofilm formation to better address their potential as anti-infective agents. We additionally analyze AMP immobilization techniques on a variety of materials, with a focus on biomedical applications. Furthermore, we summarize the advances made to date regarding the immobilization strategies of AMPs on various surfaces and their ability to prevent the adhesion of various microorganisms. Progress toward the clinical approval of AMPs in antibiotherapy is also reviewed.

Bacteria and biofilms under the influence of shear

2020 ◽  
Author(s):  
Christine Müller-Renno ◽  
Jürgen Seehase ◽  
Katharina Huttenlochner ◽  
Jonas Chodorski ◽  
Roland Ulber ◽  
...  
Keyword(s):  
Surface Energy ◽  
Biofilm Formation ◽  
Proteome Analysis ◽  
Lateral Force ◽  
Adherent Cell ◽  
Adhesion Forces ◽  
Shear Forces ◽  
Flowing Liquid ◽  
Force Microscopy ◽  
Scanning Force

<p>In our attempts to improve the biofilm formation for productive bacteria (here the gram-negative seawater bacterium Paracoccus seriniphilus), we focus on the attachment of single bacteria to a solid surface as the first step of the biofilm formation process. Beside adhesion forces and elasticity of the bacteria, we investigate the minimal detachment forces due to lateral shear forces.</p> <p>In order to investigate the influence of shear forces on already adhered bacteria in the laboratory, the Lateral Force Microscopy(LFM) was used first.The tip is moved laterally towards the adherent cell with different lateral forces until the cell detaches and thus the force required to shear the cell is determined.</p> <p>By applying LFM, we found a correlation between the applied force and the number of moved bacteria as well as between the number of detached bacteria and the surface energy of the substrate. Further, any structuring of the substrate hinders the detachment substantially [1]. In agreement with the vertical adhesion forces, the bacteria are harder to detach at pH 4 than at pH 7.</p> <p>In order to get closer to reality, the next step is to examine the (lateral) scanning force microscopic measurements under the influence of a flowing liquid and compare them with the LFM measurements. In combination with digital holography and proteome analysis, a better understanding of biofilm formation under the influence of a flowing liquid is to be achieved.</p> <p>[1] K. Huttenlochner, N. Davoudi, C. Schlegel, M. Bohley, C. Müller-Renno, J. C. Aurich, R. Ulber, and C. Ziegle "Paracoccus seriniphilus adhered on surfaces: Resistance of a seawater bacterium against shear forces under the influence of roughness, surface energy, and zeta potential of the surfaces." Biointerphases 13.5 (2018)</p>

Reduced bacterial adhesion on titanium surfaces micro-structured by ultra-short pulsed laser ablation

2016 ◽  
Vol 17 (1-2) ◽  
Author(s):  
Katharina Doll ◽  
Elena Fadeeva ◽  
Nico S. Stumpp ◽  
Sebastian Grade ◽  
Boris N. Chichkov ◽  
...  
Keyword(s):  
Laser Ablation ◽  
Bacterial Adhesion ◽  
Biofilm Formation ◽  
Pulsed Laser ◽  
Pulsed Laser Ablation ◽  
Modern Medicine ◽  
Bacterial Attachment ◽  
Titanium Surfaces ◽  
The Common ◽  
Micro Structures

AbstractImplant-associated infections still pose serious problems in modern medicine. The development of fabrication processes to generate functional surfaces, which inhibit bacterial attachment, is of major importance. Sharklet™-like as well as grooves and grid micro-structures having similar dimensions were fabricated on the common implant material titanium by ultra-short pulsed laser ablation. Investigations on the biofilm formation of

scholarly journals Antibacterial Efficacy of Iron-Oxide Nanoparticles against Biofilms on Different Biomaterial Surfaces

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Monica Thukkaram ◽  
Soundarya Sitaram ◽  
Sathish kumar Kannaiyan ◽  
Guruprakash Subbiahdoss
Keyword(s):  
Iron Oxide ◽  
Iron Oxide Nanoparticles ◽  
Bacterial Adhesion ◽  
Biofilm Formation ◽  
Polymer Brush ◽  
Oxide Nanoparticles ◽  
Implant Surface ◽  
Biofilm Growth ◽  
Biomaterial Surfaces ◽  
Coated Surfaces

Biofilm growth on the implant surface is the number one cause of the failure of the implants. Biofilms on implant surfaces are hard to eliminate by antibiotics due to the protection offered by the exopolymeric substances that embed the organisms in a matrix, impenetrable for most antibiotics and immune cells. Application of metals in nanoscale is considered to resolve biofilm formation. Here we studied the effect of iron-oxide nanoparticles over biofilm formation on different biomaterial surfaces and pluronic coated surfaces. Bacterial adhesion for 30 min showed significant reduction in bacterial adhesion on pluronic coated surfaces compared to other surfaces. Subsequently, bacteria were allowed to grow for 24 h in the presence of different concentrations of iron-oxide nanoparticles. A significant reduction in biofilm growth was observed in the presence of the highest concentration of iron-oxide nanoparticles on pluronic coated surfaces compared to other surfaces. Therefore, combination of polymer brush coating and iron-oxide nanoparticles could show a significant reduction in biofilm formation.

scholarly journals Bacterial Adhesion Forces with Substratum Surfaces and the Susceptibility of Biofilms to Antibiotics

2012 ◽  
Vol 56 (9) ◽  
pp. 4961-4964 ◽  
Author(s):  
Agnieszka K. Muszanska ◽  
M. Reza Nejadnik ◽  
Yun Chen ◽  
Edwin R. van den Heuvel ◽  
Henk J. Busscher ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Pseudomonas Aeruginosa ◽  
Silicone Rubber ◽  
Staphylococcus Epidermidis ◽  
Bacterial Adhesion ◽  
Antibiotic Susceptibility ◽  
Polymer Brush ◽  
Adhesion Forces ◽  
Content Type ◽  
Planktonic State

ABSTRACTBiofilms causing biomaterial-associated infection resist antibiotic treatment and usually necessitate the replacement of infected implants. Here we relate bacterial adhesion forces and the antibiotic susceptibility of biofilms on uncoated and polymer brush-coated silicone rubber. Nine strains ofStaphylococcus aureus,Staphylococcus epidermidis, andPseudomonas aeruginosaadhered more weakly to brush-coated silicone rubber (−0.05 ± 0.03 to −0.51 ± 0.62 nN) than to uncoated silicone rubber (−1.05 ± 0.46 to −5.1 ± 1.3 nN). Biofilms of weakly adhering organisms on polymer brush coatings remained in a planktonic state, susceptible to gentamicin, unlike biofilms formed on uncoated silicone rubber.

The Effect of Ball Pad Metallurgy and Ball Composition on Solder Ball Integrity of Plastic Ball Grid Array Packages

1998 ◽  
Author(s):  
C.H. Zhong ◽  
Sung Yi
Keyword(s):  
Failure Mode ◽  
Barrier Layer ◽  
Shear Force ◽  
Solder Ball ◽  
Ball Grid Array ◽  
Reliability Test ◽  
Shear Forces ◽  
Ball Shear ◽  
Plastic Ball ◽  
Plastic Ball Grid Array

Abstract Ball shear forces of plastic ball grid array (PBGA) packages are found to decrease after reliability test. Packages with different ball pad metallurgy form different intermetallic compounds (IMC) thus ball shear forces and failure modes are different. The characteristic and dynamic process of IMC formed are decided by ball pad metallurgy which includes Ni barrier layer and Au layer thickness. Solder ball composition also affects IMC formation dynamic process. There is basically no difference in ball shear force and failure mode for packages with different under ball pad metallurgy before reliability test. However shear force decreased and failure mode changed after reliability test, especially when packages exposed to high temperature. Major difference in ball shear force and failure mode was found for ball pad metallurgy of Ni barrier layer including Ni-P, pure Ni and Ni-Co. Solder ball composition was found to affect the IMC formation rate.

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