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.

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.

Interspecies Interactions in Dual-Species Biofilms Formed by Psychrotrophic Bacteria and the Tolerance of Sessile Communities to Disinfectants

2020 ◽  
Vol 83 (6) ◽  
pp. 951-958 ◽  
Author(s):  
LEI YUAN ◽  
NI WANG ◽  
FAIZAN A. SADIQ ◽  
GUOQING HE
Keyword(s):  
Hydrogen Peroxide ◽  
Sodium Hypochlorite ◽  
Peracetic Acid ◽  
Laser Scanning ◽  
Structural Changes ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Interspecies Interactions ◽  
Mixed Species ◽  
Psychrotrophic Bacteria

ABSTRACT Biofilms on the surface of food processing equipment act as potential reservoirs of microbial contamination. Bacterial interactions are believed to play key roles in both biofilm formation and antimicrobial tolerance. In this study, Aeromonas hydrophila, Chryseobacterium oncorhynchi, and Pseudomonas libanensis, which were previously isolated from Chinese raw milk samples, were selected to establish two dual-species biofilm models (P. libanensis plus A. hydrophila and P. libanensis plus C. oncorhynchi) on stainless steel at 7°C. Subsequently, three disinfectants, hydrogen peroxide (100 ppm), peracetic acid (100 ppm), and sodium hypochlorite (100 ppm), were used to treat the developed sessile communities for 10 min. Structural changes after exposure to disinfectants were analyzed with confocal laser scanning microscopy. The cell numbers of both A. hydrophila and C. oncorhynchi recovered from surfaces increased when grown as dual species biofilms with P. libanensis. Dual-species biofilms were more tolerant of disinfectants than were each single-species biofilm. Peracetic acid was the most effective disinfectant for removing biofilms, followed by hydrogen peroxide and sodium hypochlorite. The results expand the knowledge of mixed-species biofilms formed by psychrotrophic bacteria and will be helpful for developing effective strategies to eliminate bacterial mixed-species biofilms. HIGHLIGHTS

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.

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 Effect of bleaching on sound enamel and with early artificial caries lesions using confocal laser microscopy

2012 ◽  
Vol 23 (2) ◽  
pp. 110-115 ◽  
Author(s):  
Sandrine Bittencourt Berger ◽  
Sabrina Pavan ◽  
Paulo Henrique dos Santos ◽  
Marcelo Giannini ◽  
Ana Karina B. Bedran-Russo
Keyword(s):  
Hydrogen Peroxide ◽  
Calcium Phosphate ◽  
Fluorescence Intensity ◽  
Laser Scanning ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Significant Difference ◽  
Ph Cycling ◽  
Bovine Enamel ◽  
Caries Lesions

The aim of this study was to evaluate effect of bleaching agents on sound enamel (SE) and enamel with early artificial caries lesions (CL) using confocal laser scanning microscopy (CLSM). Eighty blocks (4 x 5 x 5 mm) of bovine enamel were used and half of them were submitted to a pH cycling model to induce CL. Eight experimental groups were obtained from the treatments and mineralization level of the enamel (SE or CL) (n=10). SE groups: G1 - unbleached (control); G2 - 4% hydrogen peroxide (4 HP); G3 - 4 HP containing 0.05% Ca (Ca); G4 - 7.5% hydrogen peroxide (7.5 HP) containing amorphous calcium phosphate (ACP). CL groups: G5 - unbleached; G6 - 4 HP; G7 - 4 HP containing Ca; G8 - 7.5 HP ACP. G2, G3, G6, G7 were treated with the bleaching agents for 8 h/day during 14 days, while G4 and G8 were exposed to the bleaching agents for 30 min twice a day during 14 days. The enamel blocks were stained with 0.1 mM rhodamine B solution and the demineralization was quantified using fluorescence intensity detected by CLSM. Data were analyzed using ANOVA and Fisher’s tests (α=0.05). For the SE groups, the bleaching treatments increased significantly the demineralization area when compared with the unbleached group. In the CL groups, no statistically significant difference was observed (p>0.05).The addition of ACP or Ca in the composition of the whitening products did not overcome the effects caused by bleaching treatments on SE and neither was able to promote remineralization of CL.

scholarly journals Effect of oil contents on gluten network during the extrusion processing

2019 ◽  
Vol 37 (No. 4) ◽  
pp. 226-231 ◽  
Author(s):  
Feng Jia ◽  
Jinshui Wang ◽  
Yu Chen ◽  
Xia Zhang ◽  
Qi Wang ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Laser Scanning ◽  
Oil Content ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Low Molecular Weight ◽  
Gluten Free ◽  
Extrusion Processing ◽  
Glutenin Macropolymer ◽  
And Control

To investigate a comparative evaluation of the gluten polymerization properties at different oil contents during the extrusion processing, the electrophoretic profiles of the gluten, free sulfhydryl (SH) compounds, the secondary structure of gluten, glutenin macropolymer contents and gluten network were measured. Five gluten samples were formulated by adding different oil contents. The low molecular weight contents of gluten decreased as well as the high molecular weight contents increased during the extrusion processing. The free SH of gluten at 8 or 10% oil content drops significantly to a minimum. The β-sheets contents of gluten have significantly difference between the treatments and control, except for 15 and 20% oil content treatments. Confocal laser scanning microscopy of mixed glutens correlated to the degree of oil contents with the gluten in the bi-continuous gluten network.

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 Endoplasmic reticulum resident proteins of normal human dermal fibroblasts are the major targets for oxidative stress induced by hydrogen peroxide

2002 ◽  
Vol 366 (3) ◽  
pp. 825-830 ◽  
Author(s):  
Dennis van der VLIES ◽  
Eward H.W. PAP ◽  
Jan Andries POST ◽  
Julio E. CELIS ◽  
Karel W.A. WIRTZ
Keyword(s):  
Hydrogen Peroxide ◽  
Endoplasmic Reticulum ◽  
Laser Scanning ◽  
Dermal Fibroblasts ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Human Dermal Fibroblasts ◽  
Normal Human ◽  
Covalently Linked ◽  
Normal Human Dermal Fibroblasts

The membrane-permeable fluorescein-labelled tyramine conjugate (acetylTyrFluo) was used to identify the proteins of normal human dermal fibroblasts most susceptible to oxidation by hydrogen peroxide [Van der Vlies, Wirtz and Pap (2001) Biochemistry 40, 7783—7788]. By exposing the cells to H2O2 (0.1mM for 10min), TyrFluo was covalently linked to target proteins. TyrFluo-labelled and [35S]Met-labelled cell lysates were mixed and subjected to two-dimensional PAGE. After Western blotting the 35S-labelled proteins were visualized by autoradiography and the TyrFluo-labelled proteins by using anti-fluorescein antibody. The TyrFluo-labelled proteins were matched with the 35S-labelled proteins and identified by comparison with our mastermap of proteins. Protein disulphide isomerase (PDI), IgG-binding protein (BiP), calnexin, endoplasmin and glucose-regulated protein 58 (endoplasmic reticulum protein 57/GRP58) were identified as targets of oxidation. All these proteins reside in the endoplasmic reticulum and are part of the protein folding machinery. In agreement, confocal laser scanning microscopy showed co-localization of TyrFluo-labelled proteins and the KDEL receptor ERD-2, a marker for the endoplasmic reticulum.

scholarly journals The Effect of Molecular Weight on the Antimicrobial Activity of Chitosan from Loligo opalescens for Food Packaging Applications

Marine Drugs ◽  
2021 ◽  
Vol 19 (7) ◽  
pp. 384
Author(s):  
Luciana C. Gomes ◽  
Sara I. Faria ◽  
Jesus Valcarcel ◽  
José A. Vázquez ◽  
Miguel A. Cerqueira ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Antimicrobial Activity ◽  
Laser Scanning ◽  
Food Packaging ◽  
Laser Scanning Microscopy ◽  
Food Storage ◽  
Poly Lactic Acid ◽  
Confocal Laser ◽  
Antibiofilm Activity ◽  
Loligo Opalescens

The growing requirement for sustainable processes has boosted the development of biodegradable plastic-based materials incorporating bioactive compounds obtained from waste, adding value to these products. Chitosan (Ch) is a biopolymer that can be obtained by deacetylation of chitin (found abundantly in waste from the fishery industry) and has valuable properties such as biocompatibility, biodegradability, antimicrobial activity, and easy film-forming ability. This study aimed to produce and characterize poly(lactic acid) (PLA) surfaces coated with β-chitosan and β-chitooligosaccharides from a Loligo opalescens pen with different molecular weights for application in the food industry. The PLA films with native and depolymerized Ch were functionalized through plasma oxygen treatment followed by dip-coating, and their physicochemical properties were assessed by Fourier-transform infrared spectroscopy, X-ray diffraction, water contact angle, and scanning electron microscopy. Their antimicrobial properties were assessed against Escherichia coli and Pseudomonas putida, where Ch-based surfaces reduced the number of biofilm viable, viable but nonculturable, and culturable cells by up to 73%, 74%, and 87%, respectively, compared to PLA. Biofilm growth inhibition was confirmed by confocal laser scanning microscopy. Results suggest that Ch films of higher molecular weight had higher antibiofilm activity under the food storage conditions mimicked in this work, contributing simultaneously to the reuse of marine waste.

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