scholarly journals Fabrication and Hydrodynamic Characterization of a Microfluidic Device for Cell Adhesion Tests in Polymeric Surfaces

Micromachines ◽  
2019 ◽  
Vol 10 (5) ◽  
pp. 303 ◽  
Author(s):  
J. Ponmozhi ◽  
J. M. R. Moreira ◽  
F. J. Mergulhão ◽  
J. B. L. M. Campos ◽  
J. M. Miranda
Keyword(s):  
Cell Adhesion ◽  
Microfluidic Device ◽  
Bacterial Adhesion ◽  
Soft Lithography ◽  
Region Of Interest ◽  
Polymeric Materials ◽  
Fabrication Method ◽  
Major Drawback ◽  
Polymeric Surfaces ◽  
Rectangular Channels

A fabrication method is developed to produce a microfluidic device to test cell adhesion to polymeric materials. The process is able to produce channels with walls of any spin coatable polymer. The method is a modification of the existing poly-dimethylsiloxane soft lithography method and, therefore, it is compatible with sealing methods and equipment of most microfluidic laboratories. The molds are produced by xurography, simplifying the fabrication in laboratories without sophisticated equipment for photolithography. The fabrication method is tested by determining the effective differences in bacterial adhesion in five different materials. These materials have different surface hydrophobicities and charges. The major drawback of the method is the location of the region of interest in a lowered surface. It is demonstrated by bacterial adhesion experiments that this drawback has a negligible effect on adhesion. The flow in the device was characterized by computational fluid dynamics and it was shown that shear stress in the region of interest can be calculated by numerical methods and by an analytical equation for rectangular channels. The device is therefore validated for adhesion tests.

Erratum — Universal method for fabricating PDMS microfluidic device using SU8, 3D printing and soft lithography

2021 ◽  
pp. 1-1
Author(s):  
Charmi Chande ◽  
Nida Riaz ◽  
Andrew House ◽  
Victoria Harbour ◽  
Hathija Noor ◽  
...  
Keyword(s):  
3D Printing ◽  
Microfluidic Device ◽  
Soft Lithography ◽  
Universal Method

scholarly journals Micropipette-Based Microfluidic Device for Monodisperse Microbubbles Generation

Micromachines ◽  
2018 ◽  
Vol 9 (8) ◽  
pp. 387
Author(s):  
Carlos Toshiyuki Matsumi ◽  
Wilson José da Silva ◽  
Fábio Kurt Schneider ◽  
Joaquim Miguel Maia ◽  
Rigoberto E. M. Morales ◽  
...  
Keyword(s):  
Electric Fields ◽  
Microfluidic Device ◽  
Soft Lithography ◽  
Low Cost ◽  
Characteristic Curve ◽  
Microfluidic Devices ◽  
Average Diameter ◽  
Internal Diameter ◽  
Medical Diagnostic ◽  
Average Size

Microbubbles have various applications including their use as carrier agents for localized delivery of genes and drugs and in medical diagnostic imagery. Various techniques are used for the production of monodisperse microbubbles including the Gyratory, the coaxial electro-hydrodynamic atomization (CEHDA), the sonication methods, and the use of microfluidic devices. Some of these techniques require safety procedures during the application of intense electric fields (e.g., CEHDA) or soft lithography equipment for the production of microfluidic devices. This study presents a hybrid manufacturing process using micropipettes and 3D printing for the construction of a T-Junction microfluidic device resulting in simple and low cost generation of monodisperse microbubbles. In this work, microbubbles with an average size of 16.6 to 57.7 μm and a polydispersity index (PDI) between 0.47% and 1.06% were generated. When the device is used at higher bubble production rate, the average diameter was 42.8 μm with increased PDI of 3.13%. In addition, a second-order polynomial characteristic curve useful to estimate micropipette internal diameter necessary to generate a desired microbubble size is presented and a linear relationship between the ratio of gaseous and liquid phases flows and the ratio of microbubble and micropipette diameters (i.e., Qg/Ql and Db/Dp) was found.

scholarly journals The Reducing Approaches of Scattering Losses in Polymer Planar Optical Waveguides

2021 ◽  
Vol 7 (1) ◽  
pp. 31-40
Author(s):  
T. Radzievskaya ◽  
N. Ivanov ◽  
S. Tarasov
Keyword(s):  
Data Transmission ◽  
Optical Waveguides ◽  
Soft Lithography ◽  
High Speed ◽  
Polymeric Materials ◽  
Polymer Materials ◽  
Advantages And Disadvantages ◽  
High Speed Data ◽  
Scattering Losses ◽  
Planar Optical Waveguides

The article presents the development prospects of planar optical waveguides for high-speed data transmission systems optoelectronic buses by polymer materials. The advantages and disadvantages of using non-specialized polymeric materials for general use are revealed. The polymer planar optical waveguides fabrication technologies are proposed. The main losses types in planar optical waveguides, the reasons for their occurrence, as well as approaches to their reduction are determined. Using the example of PDMS polymer and soft lithography technology, the technological process critical stages of polymer planar optical waveguides production are noted, which contribute to an scattering losses increase. For each stage, algorithms are proposed to prevent an scattering losses increase. These algorithms were implemented in practice in the manufacture of layouts of polymer planar optical waveguides of the optical-electronic data transmission bus.

Modification of Polymeric Surfaces With Plasmas

MRS Bulletin ◽  
1996 ◽  
Vol 21 (8) ◽  
pp. 43-45 ◽  
Author(s):  
Don M. Coates ◽  
Stephen L. Kaplan
Keyword(s):  
Surface Preparation ◽  
Polymeric Materials ◽  
Polymer Surfaces ◽  
Surface Coatings ◽  
Daily Lives ◽  
Polymeric Surfaces ◽  
Capacitively Coupled ◽  
Rf Plasmas ◽  
Plasma Treatments ◽  
Surface Chemistries

As adaptable as polymeric materials are in their many applications to our daily lives, the need exists to tailor the polymer surfaces to provide even more flexibility in regard to their uses. Plasma treatments offer an unprecedented spectrum of possible surface modifications to enhance polymers, ranging from simple topographical changes to creation of surface chemistries and coatings that are radically different from the bulk polymer. Furthermore plasma treatments are environmentally friendly and economical in regard to their use of materials.Plasma processing can be classified into at least four categories that often overlap. These are the following: (1) surface preparation by breakdown of surface oils and loose contaminates, (2) etching of new topographies, (3) surface activation by creation or grafting of new functional groups or chemically reactive, excited metastable species on the surface, and (4) deposition of monolithic, adherent surface coatings by polymerization of monomeric species on the surface. Key features of these processes will be briefly discussed, with a rudimentary introduction to the chemistries involved, as well as examples. Focus is placed on capacitively coupled radio-frequency (rf) plasmas (see Figure 1 in the article by Lieberman et al. in this issue of MRS Bulletin) since they are most commonly used in polymer treatment.

scholarly journals The Influence of Surface Topography and Wettability on Escherichia coli Removal from Polymeric Materials in the Presence of a Blood Conditioning Film

2020 ◽  
Vol 17 (20) ◽  
pp. 7368
Author(s):  
I. Devine Akhidime ◽  
Anthony J. Slate ◽  
Anca Hulme ◽  
Kathryn A. Whitehead
Keyword(s):  
Escherichia Coli ◽  
Sodium Hypochlorite ◽  
Safety Management ◽  
Polymeric Materials ◽  
Surface Characteristics ◽  
Sodium Hypochlorite Solution ◽  
Polymeric Surfaces ◽  
Atp Bioluminescence ◽  
Conditioning Film ◽  
Conditioning Films

The reduction of biofouling and the reduction of cross-contamination in the food industry are important aspects of safety management systems. Polymeric surfaces are used extensively throughout the food production industry and therefore ensuring that effective cleaning regimes are conducted is vital. Throughout this study, the influence of the surface characteristics of three different polymeric surfaces, polytetrafluoroethylene (PTFE), poly(methyl methacrylate) (PMMA) and polyethylene terephthalate (PET), on the removal of Escherichia coli using a wipe clean method utilising 3% sodium hypochlorite was determined. The PTFE surfaces were the roughest and demonstrated the least wettable surface (118.8°), followed by the PMMA (75.2°) and PET surfaces (53.9°). Following cleaning with a 3% sodium hypochlorite solution, bacteria were completely removed from the PTFE surfaces, whilst the PMMA and PET surfaces still had high numbers of bacteria recovered (1.2 × 107 CFU/mL and 6.3 × 107 CFU/mL, respectively). When bacterial suspensions were applied to the surfaces in the presence of a blood conditioning film, cleaning with sodium hypochlorite demonstrated that no bacteria were recovered from the PMMA surface. However, on both the PTFE and PET surfaces, bacteria were recovered at lower concentrations (2.0 × 102 CFU/mL and 1.3 × 103 CFU/mL, respectively). ATP bioluminescence results demonstrated significantly different ATP concentrations on the surfaces when soiled (PTFE: 132 relative light units (RLU), PMMA: 80 RLU and PET: 99 RLU). Following cleaning, both in the presence and absence of a blood conditioning film, all the surfaces were considered clean, producing ATP concentrations in the range of 0–2 RLU. The results generated in this study demonstrated that the presence of a blood conditioning film significantly altered the removal of bacteria from the polymeric surfaces following a standard cleaning regime. Conditioning films which represent the environment where the surface is intended to be used should be a vital part of the test regime to ensure an effective disinfection process.

scholarly journals Antibacterial Activity and Cytotoxicity of Immobilized Glucosamine/Chondroitin Sulfate on Polylactic Acid Films

Polymers ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1186 ◽  
Author(s):  
Ilkay Karakurt ◽  
Kadir Ozaltin ◽  
Daniela Vesela ◽  
Marian Lehocky ◽  
Petr Humpolíček ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Synergistic Effect ◽  
Chondroitin Sulfate ◽  
Polylactic Acid ◽  
Photoelectron Spectroscopy ◽  
Polymeric Materials ◽  
Bactericidal Effect ◽  
In Vitro Cytotoxicity ◽  
Major Drawback

Polylactic acid (PLA) is one of the most produced polymeric materials, due to its exceptional chemical and mechanical properties. Some of them, such as biodegradability and biocompatibility, make them attractive for biomedical applications. Conversely, the major drawback of PLA in the biomedical field is their vulnerability to bacterial contamination. This study focuses on the immobilization of saccharides onto the PLA surface by a multistep approach, with the aim of providing antibacterial features and evaluting the synergistic effect of these saccharides. In this approach, after poly (acrylic acid) (PAA) brushes attached non-covalently to the PLA surface via plasma post-irradiation grafting technique, immobilization of glucosamine (GlcN) and chondroitin sulfate (ChS) to the PAA brushes was carried out. To understand the changes in surface properties, such as chemical composition, surface topography and hydrophilicity, the untreated and treated PLA films were analyzed using various characterization techniques (contact angle, scanning electron microscopy, X-ray photoelectron spectroscopy). In vitro cytotoxicity assays were investigated by the methyl tetrazolium test. The antibacterial activity of the PLA samples was tested against Escherichia coli and Staphylococcus aureus bacteria strains. Plasma-treated films immobilized with ChS and GlcN, separately and in combination, demonstrated bactericidal effect against the both bacteria strains and also the results revealed that the combination has no synergistic effect on antibacterial action.

Controlling Cell Adhesion on Human Tissue by Soft Lithography

Langmuir ◽  
2004 ◽  
Vol 20 (10) ◽  
pp. 4155-4161 ◽  
Author(s):  
Christina J. Lee ◽  
Mark S. Blumenkranz ◽  
Harvey A. Fishman ◽  
Stacey F. Bent
Keyword(s):  
Cell Adhesion ◽  
Human Tissue ◽  
Soft Lithography

Chemotaxis of Mesenchymal Stem Cells in a Microfluidic Device

2012 ◽  
Vol 1498 ◽  
pp. 67-72
Author(s):  
Ruth Choa ◽  
Manav Mehta ◽  
Kangwon Lee ◽  
David Mooney
Keyword(s):  
Stem Cells ◽  
Mesenchymal Stem Cells ◽  
Microfluidic Device ◽  
Soft Lithography ◽  
Center Of Mass ◽  
Cell Movement ◽  
Microfluidic Devices ◽  
Chemokine Gradient ◽  
Long Time ◽  
Stable Linear

ABSTRACTAdult bone marrow derived mesenchymal stem cells (MSCs) represent an important source of cells for tissue regeneration. Control of MSC migration and homing is still unclear. The goal of this study was to identify potent chemoattractants for MSCs and characterize MSC chemotaxis using a microfluidic device as a model system and assay platform. The three chemokines compared in this study were CXCL7, CXCL12, and AMD 3100.Microfluidic devices made of polydimethysiloxane (PDMS) were fabricated by soft lithography techniques and designed to generate a stable linear chemokine gradient. Cell movements in response to the gradient were captured by timelapse photos and tracked over 24 hours. Chemokine potency was measured via several chemotaxis parameters including: velocity in the direction of interest (V), center of mass (Mend), forward migration indice (YFMI). The migratory paths of the cells were mapped onto a displacement plot and compared.The following results were measured in the direction of interest (towards higher concentrations of chemokine): For velocity, only cells exposed to CXCL12 had a statistically significant (p=.014) average velocity (V=0.19 ± 0.07 um/min) when compared to the control condition (V=0.06 ±0 .04 um/min). For the center of mass, where the displacement of cells from their starting positions were compared, again only CXCL12 (Mend= 53.9 ± 10.8 um) stimulated statistically significant (p = .013) displacement of cells compared to the control condition (Mend = 19.3 ± 16.1 um). For the forward migration index, the efficiency of cell movement was measured. Indices in both the CXCL12 (YFIM = 0.19 ± 0.08) and CXCL7 (YFIM = 0.09 ±0.03) conditions were statistically significant (p = .023 for CXCL12 and p = .035 for CXCL7) when compared with the control index (YFIM = .04 ± .02).This study demonstrated the use of microfluidic devices as a viable platform for chemotaxis studies. A stable linear chemokine gradient was maintained over a long time scale to obtain cell migration results. CXCL12 was quantitatively determined to be the most potent chemoattractant in this research; these chemoattractive properties promote its use in future developments to control MSC homing.

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