scholarly journals HYDROGEL ANTIBACTERIAL COATING FOR SILICONE MEDICAL DEVICES

2021 ◽  
Vol 26 ◽  
pp. 135-147
Author(s):  
Kamil Kopeć ◽  
◽  
Michał Żuk ◽  
Tomasz Ciach ◽  
Keyword(s):  
Medical Devices ◽  
Laser Scanning ◽  
Micrococcus Luteus ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Hydroxyl Groups ◽  
Layer By Layer ◽  
Alginate Hydrogel ◽  
Pdms Surface ◽  
Hydrogel Coating

Effective antibacterial coatings are in demand in medicine, especially for urological medical devices such as catheters and stents. We propose the production method of an antibacterial hydrogel coating on polydimethylsiloxane (PDMS, silicone), a popular surface for medical materials. The coating process consists of the following steps: PDMS surface activation (introduction of hydroxyl groups), silanisation (introduction of amine groups) and application of chitosan/alginate hydrogel with the addition of lysozyme as an antibacterial agent using the layer-by-layer method. We investigated the effect of polyion concentration on the coating mass, swelling ratio and stability. We analysed the adsorption of Micrococcus luteus, Escherichia coli and Proteus rettgeri on a PDMS surface using confocal laser scanning microscopy. The chitosan/alginate hydrogel coating with immobilised lysozyme protected the PDMS surface against adhesion for all three tested bacterial strains.

scholarly journals Studies on the Mechanisms of Anti-Inflammatory Activity of Heparin- and Hyaluronan-Containing Multilayer Coatings—Targeting NF-κB Signalling Pathway

2020 ◽  
Vol 21 (10) ◽  
pp. 3724 ◽  
Author(s):  
Hala Alkhoury ◽  
Adrian Hautmann ◽  
Bodo Fuhrmann ◽  
Frank Syrowatka ◽  
Frank Erdmann ◽  
...  
Keyword(s):  
Signal Transduction ◽  
Laser Scanning ◽  
Adhesion Formation ◽  
Laser Scanning Microscopy ◽  
Inflammatory Activity ◽  
Confocal Laser ◽  
Layer By Layer ◽  
Ethylene Imine ◽  
Inflammatory Reactions ◽  
Anti Inflammatory

The use of implants can be hampered by chronic inflammatory reactions, which may result in failure of the implanted device. To prevent such an outcome, the present study examines the anti-inflammatory properties of surface coatings made of either hyaluronic acid (HA) or heparin (Hep) in combination with chitosan (Chi) prepared as multilayers through the layer-by-layer (LbL) technique. The properties of glycosaminoglycan (GAG)-modified surfaces were characterized in terms of surface topography, thickness and wettability. Results showed a higher thickness and hydrophilicity after multilayer formation compared to poly (ethylene imine) control samples. Moreover, multilayers containing either HA or Hep dampened the inflammatory response visible by reduced adhesion, formation of multinucleated giant cells (MNGCs) and IL-1β release, which was studied using THP-1 derived macrophages. Furthermore, investigations regarding the mechanism of anti-inflammatory activity of GAG were focused on nuclear transcription factor-кB (NF-κB)-related signal transduction. Immunofluorescence staining of the p65 subunit of NF-κB and immunoblotting were performed that showed a significant decrease in NF-κB level in macrophages on GAG-based multilayers. Additionally, the association of FITC-labelled GAG was evaluated by confocal laser scanning microscopy and flow cytometry showing that macrophages were able to associate with and take up HA and Hep. Overall, the Hep-based multilayers demonstrated the most suppressive effect making this system most promising to control macrophage activation after implantation of medical devices. The results provide an insight on the anti-inflammatory effects of GAG not only based on their physicochemical properties, but also related to their mechanism of action toward NF-κB signal transduction.

Preparation, Characterization and Properties Evaluation of Buprofezin Nanocomposites Obtained by Polyelectrolytes Assembly

2011 ◽  
Vol 183-185 ◽  
pp. 1677-1681 ◽  
Author(s):  
Zhe Zhang ◽  
De Fu Chi ◽  
Jia Yu
Keyword(s):  
Laser Scanning ◽  
Orthogonal Experiment ◽  
Drug Loading ◽  
In Vitro Release ◽  
Average Diameter ◽  
Laser Scanning Microscopy ◽  
Release Time ◽  
Confocal Laser ◽  
Layer By Layer

Buprofezin (BPF) microcrystals were directly encapsulated with nature polysaccharides chitosan (CHI) and sodium alginate (ALG) through layer-by-layer (LbL) self-assembly. The coated colloids were characterized using confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). The surface of the coated microcrystal was smoothened and the coating was uniform. Different concentrations of the ALG, CHI, BPF and CaCl2 were selected as the influencing factors, and then, the microcapsules were optimized by orthogonal experiment. The size distribution of microcapsules was determined by Laser Diffraction Size Analyzer. It showed statistically normal distribution. The average diameter of BPF was 1.5m. The encapsulation efficiency of the BPF loaded microparticles was about 67.2±0.73%. The drug loading content was about 66.7±0.31% after encapsulated. The in vitro release experiments revealed that the polyelectrolytes prolonged the release time of the encapsulated BPF microcrystals.

Layer-by-Layer Engineered Microreactors for Bio-Polymerization of 4-(2-aminoethyl) phenol hydrochloride

2003 ◽  
Vol 782 ◽  
Author(s):  
R. Ghan ◽  
T. Shutava ◽  
A. Patel ◽  
V. John ◽  
Y. Lvov
Keyword(s):  
Hydrogen Peroxide ◽  
Molecular Weight ◽  
Laser Scanning ◽  
Laser Scanning Microscopy ◽  
Polymerization Reaction ◽  
Confocal Laser ◽  
Layer By Layer ◽  
Polymeric Form ◽  
Characterization Methods ◽  
Concentrated Solution

ABSTRACTThis study presents the results of polymerization of phenol to yield fluorescent polymer encapsulated within shells fabricated via layer-by-layer (L-b-L) assembly. Hollow polyelectrolyte microcapsules (shells) were prepared using weakly cross-linked melamine formaldehyde (MF) particles. Dissolution of the MF cores was achieved by changing the pH of the solution. Horseradish peroxidase (HRP), the catalyzing enzyme, was loaded in these capsules by taking advantage of the “open/close” mechanism of the capsules by altering the pH. The empty shells were then suspended in a concentrated solution of monomer. Since the monomer is a low molecular weight species, it freely permeates through the polyion wall into the shells. Addition of aliquots of hydrogen peroxide initiated the polymerization reaction and the polymer formed from the ensuing reaction was confined in the shells due to its high molecular weight. The model used for demonstrating this synthesis is polymerization of 4-(2-aminoethyl) phenol hydrochloride commonly known as tyramine hydrochloride to its corresponding polymeric form by reacting it with hydrogen peroxide. Fluorescence spectrometry (FS), confocal laser scanning microscopy (CLSM), and atomic force microscopy (AFM) were the characterization methods employed to confirm polymerization in situ shells.

Cell labeling efficiency of layer-by-layer self-assembly modified silica nanoparticles

2009 ◽  
Vol 24 (4) ◽  
pp. 1317-1321 ◽  
Author(s):  
Gang Liu ◽  
Jing Tian ◽  
Chen Liu ◽  
Hua Ai ◽  
Zhongwei Gu ◽  
...  
Keyword(s):  
Silica Nanoparticles ◽  
Self Assembly ◽  
Laser Scanning ◽  
Control Cell ◽  
Silica Nanoparticle ◽  
Laser Scanning Microscopy ◽  
Cell Labeling ◽  
Cell Uptake ◽  
Confocal Laser ◽  
Layer By Layer

In the present study, we compared cytotoxicity and cell uptake of silica nanoparticles with four different surface coatings generated through layer-by-layer self-assembly. Rabbit mesenchymal stem cells (rMSCs) were labeled with silica nanoparticles of different coatings including poly(ethyleneimine) (PEI), poly(allylamine hydrochloride) (PAH), poly(anetholesulfonic acid, sodium salt) (PAS), and dextran sulfate. The MTT [3-(4, 5-dimethylthiazol-2)-2, 5-diphenyl-2H-tetrazolium bromide] test was performed to quantify the cell biocompatibility. The cellular uptake of those silica nanoparticles was determined by flow cytometry and confocal laser scanning microscopy. The results showed that all examined silica nanoparticles were stable in aqueous phase with high monodispersity. Labeled rMSCs are unaffected in their viability, apoptosis, and differentiation capacities. The silica nanoparticle-coated synthetic polycations such as PEI or PAH have higher cell internalization than negatively charged polyelectrolytes. The ability to control cell uptake of different particles may have applications in cell labeling, cell separation, and other biomedical applications.

scholarly journals Coaggregation by the Freshwater Bacterium Sphingomonas natatoria Alters Dual-Species Biofilm Formation

2009 ◽  
Vol 75 (12) ◽  
pp. 3987-3997 ◽  
Author(s):  
K. R. Min ◽  
A. H. Rickard
Keyword(s):  
Glass Surface ◽  
Laser Scanning ◽  
Micrococcus Luteus ◽  
Single Species ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Biofilm Growth ◽  
Biofilm Development ◽  
Glass Surfaces ◽  
Sphingomonas Natatoria

ABSTRACTCoaggregation is hypothesized to enhance freshwater biofilm development. To investigate this hypothesis, the ability of the coaggregating bacteriumSphingomonas natatoriato form single- and dual-species biofilms was studied and compared to that of a naturally occurring spontaneous coaggregation-deficient variant. Attachment assays using metabolically inactive cells were performed using epifluorescence and confocal laser scanning microscopy. Under static and flowing conditions, coaggregatingS. natatoria2.1gfp cells adhered to glass surfaces to form diaphanous single-species biofilms. When glass surfaces were precoated with coaggregation partnerMicrococcus luteus2.13 cells,S. natatoria2.1gfp cells formed densely packed dual-species biofilms. The addition of 80 mM galactosamine, which reverses coaggregation, mildly reduced adhesion to glass but inhibited the interaction and attachment to glass-surface-attachedM. luteus2.13 cells. As opposed to wild-type coaggregating cells, coaggregation-deficientS. natatoria2.1COGgfp variant cells were retarded in colonizing glass and did not interact with glass-surface-attachedM. luteus2.13 cells. To determine if coaggregation enhances biofilm growth and expansion, viable coaggregatingS. natatoria2.1gfp cells or the coaggregation-deficient variantS. natatoria2.1COGgfp cells were coinoculated in flow cells with viableM. luteus2.13 cells and allowed to grow together for 96 h. CoaggregatingS. natatoria2.1gfp cells outcompetedM. luteus2.13 cells, and 96-h biofilms were composed predominantly ofS. natatoria2.1gfp cells. Conversely, when coaggregation-deficientS. natatoria2.1COGgfp cells were coinoculated withM. luteus2.13 cells, the 96-h biofilm contained few coaggregation-deficientS. natatoria2.1 cells. Thus, coaggregation promotes biofilm integration by facilitating attachment to partner species and likely contributes to the expansion of coaggregatingS. natatoria2.1 populations in dual-species biofilms through competitive interactions.

3-D imaging of cells using a confocal laser scanning microscope and digital image processing

1988 ◽  
Vol 46 ◽  
pp. 96-97
Author(s):  
Thomas M. Jovin ◽  
Michel Robert-Nicoud ◽  
Donna J. Arndt-Jovin ◽  
Thorsten Schormann
Keyword(s):  
Laser Scanning ◽  
Confocal Laser Scanning Microscope ◽  
Laser Scanning Microscopy ◽  
Confocal Laser Scanning ◽  
Confocal Laser ◽  
Scanning Microscope ◽  
Laser Scanning Microscope ◽  
Biochemical Processes ◽  
Adjacent Structures

Light microscopic techniques for visualizing biomolecules and biochemical processes in situ have become indispensable in studies concerning the structural organization of supramolecular assemblies in cells and of processes during the cell cycle, transformation, differentiation, and development. Confocal laser scanning microscopy offers a number of advantages for the in situ localization and quantitation of fluorescence labeled targets and probes: (i) rejection of interfering signals emanating from out-of-focus and adjacent structures, allowing the “optical sectioning” of the specimen and 3-D reconstruction without time consuming deconvolution; (ii) increased spatial resolution; (iii) electronic control of contrast and magnification; (iv) simultanous imaging of the specimen by optical phenomena based on incident, scattered, emitted, and transmitted light; and (v) simultanous use of different fluorescent probes and types of detectors.We currently use a confocal laser scanning microscope CLSM (Zeiss, Oberkochen) equipped with 3-laser excitation (u.v - visible) and confocal optics in the fluorescence mode, as well as a computer-controlled X-Y-Z scanning stage with 0.1 μ resolution.

Vacuoles Induced in Mammalian Cells by Helicobacter Cytotoxin are Acidic Organelles

1990 ◽  
Vol 48 (3) ◽  
pp. 168-169
Author(s):  
M. H. Chestnut ◽  
C. E. Catrenich
Keyword(s):  
Acridine Orange ◽  
Mammalian Cells ◽  
Laser Scanning ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Ulcer Disease ◽  
Gastroduodenal Disease ◽  
H Pylori

Helicobacter pylori is a non-invasive, Gram-negative spiral bacterium first identified in 1983, and subsequently implicated in the pathogenesis of gastroduodenal disease including gastritis and peptic ulcer disease. Cytotoxic activity, manifested by intracytoplasmic vacuolation of mammalian cells in vitro, was identified in 55% of H. pylori strains examined. The vacuoles increase in number and size during extended incubation, resulting in vacuolar and cellular degeneration after 24 h to 48 h. Vacuolation of gastric epithelial cells is also observed in vivo during infection by H. pylori. A high molecular weight, heat labile protein is believed to be responsible for vacuolation and to significantly contribute to the development of gastroduodenal disease in humans. The mechanism by which the cytotoxin exerts its effect is unknown, as is the intracellular origin of the vacuolar membrane and contents. Acridine orange is a membrane-permeant weak base that initially accumulates in low-pH compartments. We have used acridine orange accumulation in conjunction with confocal laser scanning microscopy of toxin-treated cells to begin probing the nature and origin of these vacuoles.

Use of confocal laser scanning microscopy and a computer model to understand ink cavitation and filamentation

TAPPI Journal ◽  
2010 ◽  
Vol 9 (10) ◽  
pp. 7-15
Author(s):  
HANNA KOIVULA ◽  
DOUGLAS BOUSFIELD ◽  
MARTTI TOIVAKKA
Keyword(s):  
Laser Scanning ◽  
Confocal Laser Scanning Microscope ◽  
Laser Scanning Microscopy ◽  
Confocal Laser Scanning ◽  
Confocal Laser ◽  
Print Quality ◽  
Length Scale ◽  
Offset Printing ◽  
Significant Difference ◽  
Printing Speed

In the offset printing process, ink film splitting has an important impact on formation of ink filaments. The filament size and its distribution influence the leveling of ink and hence affect ink setting and the print quality. However, ink filaments are difficult to image due to their short lifetime and fine length scale. Due to this difficulty, limited work has been reported on the parameters that influence filament size and methods to characterize it. We imaged ink filament remains and quantified some of their characteristics by changing printing speed, ink amount, and fountain solution type. Printed samples were prepared using a laboratory printability tester with varying ink levels and operating settings. Rhodamine B dye was incorporated into fountain solutions to aid in the detection of the filaments. The prints were then imaged with a confocal laser scanning microscope (CLSM) and images were further analyzed for their surface topography. Modeling of the pressure pulses in the printing nip was included to better understand the mechanism of filament formation and the origin of filament length scale. Printing speed and ink amount changed the size distribution of the observed filament remains. There was no significant difference between fountain solutions with or without isopropyl alcohol on the observed patterns of the filament remains.

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