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Enzyme hydrogel

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https://www.readbyqxmd.com/read/29316144/quantitative-comparison-of-enzyme-immobilization-strategies-for-glucose-biosensing-in-real-time-using-fast-scan-cyclic-voltammetry-coupled-with-carbon-fiber-microelectrodes
#1
Samantha K Smith, Leyda Z Lugo-Morales, Christina Tang, Saahj P Gosrani, Christie A Lee, James G Roberts, Stephen W Morton, Gregory S McCarty, Saad A Khan, Leslie A Sombers
Electrochemical monitoring of non-electroactive species requires a biosensor that is stable and selective, with sensitivity to physiological concentrations of targeted analytes. We have combined glucose oxidase-modified carbon-fiber microelectrodes with fast-scan cyclic voltammetry for real-time measurements of glucose fluctuations in brain tissue. Work presented herein quantitatively compares three approaches to enzyme immobilization on the microelectrode surface - physical adsorption, hydrogel entrapment, and entrapment in electrospun nanofibers...
January 9, 2018: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
https://www.readbyqxmd.com/read/29309083/multiple-stimuli-responsive-selenium-functionalized-biodegradable-starch-based-hydrogels
#2
Tongbing Sun, Caizhen Zhu, Jian Xu
Novel biodegradable diselenide cross-linked starch-based hydrogels were synthesized via free radical copolymerization, which serve as stimuli-responsive drug release materials composed of starch chain backbones with an enzyme hydrolysis property and selenium-containing cross-linkers with a redox responsive cleavage property. Rhodamine B (RB) loaded starch-based hydrogels were prepared in order to investigate their stimuli-responsive release behaviours. In the presence of external redox agents, the enzyme stimuli as well as the mixture of the above stimuli, the prepared starch-based hydrogels exhibit controlled multi-responsive release behavior of RB...
January 8, 2018: Soft Matter
https://www.readbyqxmd.com/read/29282971/biocatalytic-self-assembly-on-magnetic-nanoparticles
#3
Maria Paola Conte, Jugal Kishore Kishore Sahoo, Yousef M Abul-Haija, King Hang Aaron Lau, Rein V Ulijn
Combining (bio-)catalysis and molecular self-assembly provides an effective approach for the production and processing of self-assembled materials, by exploiting catalysis to direct the assembly kinetics and hence control the formation of ordered nanostructures. Applications of (bio-)catalytic self-assembly in biologically interfacing systems and in nanofabrication have recently been reported. Inspired by self-assembly in biological cells, efforts to confine catalysts on flat or patterned surfaces to exert spatial control over molecular gelator generation and nanostructure self-assembly have also emerged...
December 28, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/29247536/three-dimensional-liver-derived-extracellular-matrix-hydrogel-promotes-liver-organoids-function
#4
Mona Saheli, Mohammadmajid Sepantafar, Behshad Pournasr, Zahra Farzaneh, Massoud Vosough, Abbas Piryaei, Hossein Baharvand
An important advantage of employing extracellular matrix (ECM)-derived biomaterials in tissue engineering is the ability to tailor the biochemical and physical microenvironment of the cells. This study aims to assess whether three-dimensional (3D) liver-derived ECM hydrogel (LEMgel) promotes physiological function of liver organoids generated by self-organization of human hepatocarcinoma cells together with human mesenchymal and endothelial cells. We have optimized the decellularization method to fabricate liver ECM derived from sheep to preserve the greatest content of glycosaminoglycans, collagen, laminin and fibronectin in produced LEMgel...
December 16, 2017: Journal of Cellular Biochemistry
https://www.readbyqxmd.com/read/29247379/label-free-electrochemical-immunosensor-for-ultrasensitive-detection-of-neuron-specific-enolase-based-on-enzyme-free-catalytic-amplification
#5
Shuang Yin, Lihua Zhao, Zhanfang Ma
Enzyme-free catalytic amplification is of great significance for sensitive label-free electrochemical immunosensors. In this study, an enzyme-free catalytic amplification based label-free amperometric immunosensor was developed for sensitive detection of neuron-specific enolase (NSE) by use of a AuPd nanoparticle-multiwalled carbon nanotube (AuPd-MWCNT) composite, ferrocenecarboxaldehyde (Fc-CHO), and chitosan hybrid hydrogel. The intrinsic virtues of chitosan not only resulted in bioactivity of the attached antibodies and made the other component of the immunosensor easier to fix on the electrode, but also imparted abundant binding sites to the hydrogel to condense Fc-CHO to achieve the initial signal amplification...
December 15, 2017: Analytical and Bioanalytical Chemistry
https://www.readbyqxmd.com/read/29235511/production-of-lignin-based-insoluble-polymers-anionic-hydrogels-by-c-versicolor
#6
Ivana Brzonova, Evguenii I Kozliak, Anastasia A Andrianova, Audrey LaVallie, Alena Kubátová, Yun Ji
Unlike previous lignin biodegradation studies, white rot fungi were used to produce functional biopolymers from Kraft lignin. Lignin-based polymers (hydrogel precursors) partially soluble in both aqueous and organic solvents were produced employing a relatively fast (6 days) enzymation of Kraft lignin with basidiomycetes, primarily Coriolus versicolor, pre-grown on kenaf/lignin agar followed by either vacuum evaporation or acid precipitation. After drying followed by a treatment with alkaline water, this intermediate polymer became a pH-sensitive anionic hydrogel insoluble in either aqueous or organic solvents...
December 13, 2017: Scientific Reports
https://www.readbyqxmd.com/read/29233750/fibrin-hydrogels-as-a-xenofree-and-rapidly-degradable-support-for-transplantation-of-retinal-pigment-epithelium-monolayers
#7
Jarel K Gandhi, Zahid Manzar, Lori A Bachman, Cynthia Andrews-Pfannkoch, Travis Knudsen, Matthew Hill, Hannah Schmidt, Raymond Iezzi, Jose S Pulido, Alan D Marmorstein
Recent phase 1 trials of embryonic stem cell and induced pluripotent stem cell (iPSCs) derived RPE transplants for the treatment of macular degeneration have demonstrated the relative safety of this process. However, there is concern over clumping, thickening, folding, and wrinkling of the transplanted RPE. To deliver a flat RPE monolayer, current phase 1 trials are testing synthetic substrates for RPE transplantation. These substrates, however, cause localized inflammation and fibrosis in animal models due to long degradation times...
December 9, 2017: Acta Biomaterialia
https://www.readbyqxmd.com/read/29229249/enzyme-mediated-tissue-adhesive-hydrogels-for-meniscus-repair
#8
Su-Hwan Kim, Young-Hyeon An, Hwan D Kim, Kyungmin Kim, Sang-Hyuk Lee, Hyun-Gu Yim, Byung-Gee Kim, Nathaniel S Hwang
Meniscus tissues have limited regenerative capacity once damaged. The treatment options for the meniscus tissue regeneration have been limited to arthroscopic meniscectomy or surgical interventions. The injectable hydrogels based system would provide an alternative to the conventional meniscus therapy by providing a minimally invasive treatment alternative. Here we utilized enzyme-based approaches to fabricate tissue adhesive hydrogels for meniscus repair. Tyramine (TA) conjugated hyaluronic acid (TA-HA) and gelatin are susceptible to tyrosinase (TYR)-mediated crosslinking in vitro and in vivo...
December 8, 2017: International Journal of Biological Macromolecules
https://www.readbyqxmd.com/read/29218519/glucose-transport-activity-measured-in-giant-vesicles
#9
Jesper S Hansen, Karin Lindkvist-Petersson
Incorporation of membrane proteins and internal reporter systems directly into giant vesicles, during their formation from a hydrogel surface, has emerged as a promising new concept in membrane protein characterization. Here, we provide the detailed protocol for a glucose transporter activity assay based on giant vesicles containing a fluorescent enzyme-linked reporter system internally. This assay is applicable for the functional analysis of a variety of hexose-transporting proteins. We furthermore believe that it can aid in the development of drugs targeting hexose transporters...
2018: Methods in Molecular Biology
https://www.readbyqxmd.com/read/29211452/promoted-chondrogenesis-of-co-cultured-chondrocytes-and-mesenchymal-stem-cells-under-hypoxia-using-in-situ-forming-degradable-hydrogel-scaffolds
#10
Xiaobin Huang, Yong Hou, Leilei Zhong, Dechun Huang, Hongliang Qian, Marcel Karperien, Wei Chen
We investigated the effects of different oxygen tension (21% and 2.5% O2) on the chondrogenesis of different cell systems cultured in pH-degradable PVA hydrogels including human articular chondrocytes (hACs), human mesenchymal stem cells (hMSCs) and their co-cultures with a hAC/hMSC ratio of 20/80. These hydrogels were prepared with vinyl ether acrylate-functionalized PVA (PVA-VEA) and thiolated PVA-VEA (PVA-VEA-SH) via Michael-type addition reaction. The rheology tests determined the gelation of the hydrogels was controlled within 2-7 min dependent on the polymer concentrations...
December 6, 2017: Biomacromolecules
https://www.readbyqxmd.com/read/29195274/self-assembly-of-telechelic-tyrosine-end-capped-peo-star-polymers-in-aqueous-solution
#11
Charlotte J C Edwards-Gayle, Francesca Greco, Ian W Hamley, Robert P Rambo, Mehedi Reza, Janne Ruokolainen, Dimitrios Skoulas, Hermis Iatrou
We investigate the self-assembly of two telechelic star polymer-peptide conjugates based on poly(ethylene oxide) (PEO) four-arm star polymers capped with oligotyrosine. The conjugates were prepared via N-carboxy anhydride (NCA)-mediated ring-opening polymerization from PEO star polymer macroinitiators. Self-assembly occurs above a critical aggregation concentration determined via fluorescence probe assays. Peptide conformation was examined using circular dichroism spectroscopy. The structure of self-assembled aggregates was probed using small-angle X-ray Scattering (SAXS) and cryogenic transmission electron microscopy (Cryo-TEM)...
December 1, 2017: Biomacromolecules
https://www.readbyqxmd.com/read/29192297/rapid-spheroid-clearing-on-a-microfluidic-chip
#12
Tomas Silva Santisteban, Omid Rabajania, Iana Kalinina, Stephen Robinson, Matthias Meier
Spheroids are three-dimensional (3D) cell cultures that aim to bridge the gap between the use of whole animals and cellular monolayers. Microfluidics is regarded as an enabling technology to actively control the chemical environment of 3D cell cultures. Although a wide variety of platforms have been developed to handle spheroid cultures, the development of analytical systems for spheroids remains a major challenge. In this study, we engineered a microfluidic large-scale integration (mLSI) chip platform for tissue-clearing and imaging...
December 1, 2017: Lab on a Chip
https://www.readbyqxmd.com/read/29189924/immobilization-in-polyvinyl-alcohol-hydrogel-enhances-yeast-storage-stability-and-reusability-of-recombinant-laccase-producing-s-cerevisiae
#13
Klára Herkommerová, Jana Zemančíková, Hana Sychrová, Zuzana Antošová
OBJECTIVES: To improve the storage stability and reusability of various yeast strains and species by immobilization in polyvinyl alcohol (PVA) hydrogel particles. RESULTS: Debaryomyces hansenii, Pichia sorbitophila, Saccharomyces cerevisiae, Yarrowia lipolytica, and Zygosaccharomyces rouxii were immobilized in PVA particles using LentiKats technology and stored in sterile water at 4 °C. The immobilization improved the survival of all species; however, the highest storage stability was achieved for S...
November 30, 2017: Biotechnology Letters
https://www.readbyqxmd.com/read/29180255/nanoparticle-loaded-hydrogels-as-a-pathway-for-enzyme-triggered-drug-release-in-ophthalmic-applications
#14
Michelle Åhlén, Gopi Krishna Tummala, Albert Mihranyan
The aim of this study was to develop nanoparticle loaded hydrogel based contact lenses that could be used for ocular drug delivery. Two potential contact lens platforms for controlled ophthalmic drug delivery were developed by incorporating chitosan-poly(acrylic acid) nanoparticles into polyvinyl alcohol (PVA) hydrogels and in-situ gelled nanoparticles and cellulose nanocrystals (CNC) in PVA lenses. The nanoparticles were shown to disintegrate in a physiological 0.2 mM concentration of lysozyme resulting from the hydrolysis of the chitosan chains by lysozyme...
November 24, 2017: International Journal of Pharmaceutics
https://www.readbyqxmd.com/read/29172544/a-substrate-selective-enzyme-catalysis-assembly-strategy-for-oligopeptide-hydrogel-assisted-combinatorial-protein-delivery
#15
Tianyue Jiang, Shiyang Shen, Tong Wang, Mengru Li, Bingfang He, Ran Mo
Oligopeptide hydrogels for localized protein delivery have considerable potential to reduce systemic side effects but maximize therapeutic efficacy. Although enzyme catalysis to induce formation of oligopeptide hydrogels has the merits of unique regio- and enantioselectivity and mild reaction conditions, it may cause the impairment of function and activity of the encapsulated proteins by proteolytic degradation during gelation. Here we report a novel enzyme-catalysis strategy for self-assembly of oligopeptide hydrogels using an engineered protease nanocapsule with tunable substrate selectivity...
November 27, 2017: Nano Letters
https://www.readbyqxmd.com/read/29161461/ruthenium-crosslinked-hydrogels-with-rapid-visible-light-degradation
#16
Teresa Rapp, Chris Highley, Brian Manor, Jason Burdick, Ivan J Dmochowski
Incorporation of photoresponsive molecules within soft materials can provide spatiotemporal control over bulk properties, and address challenges in targeted delivery and mechanical variability. However, the kinetics of in situ photochemical reactions are often slow and typically employ ultraviolet wavelengths. Here, we present a novel photoactive crosslinker Ru(bipyridine)2(3-pyridinaldehyde)2 (RuAldehyde), which was reacted with hydrazide-functionalized hyaluronic acid to form hydrogels capable of encapsulating protein cargo...
November 21, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/29157289/vitamin-c-plus-hydrogel-facilitates-bone-marrow-stromal-cell-mediated-endometrium-regeneration-in-rats
#17
Huan Yang, Su Wu, Ran Feng, Junjiu Huang, Lixiang Liu, Feng Liu, Yuqing Chen
BACKGROUND: Intrauterine adhesion (IUA) is a common uterine cavity disease which can be caused by mechanical damage that may eventually lead to infertility and pregnancy abnormalities. Since the effect of therapeutic drugs appears disappointing, cell therapy has emerged as an alternative choice for endometrium regeneration. The aim of this study is to investigate whether the combination of hydrogel Pluronic F-127 (PF-127), Vitamin C (Vc), and a bone marrow stromal cell (BMSC) mixture could be a feasible strategy to improve the endometrial regeneration in a mechanical damage model of IUA in rats...
November 21, 2017: Stem Cell Research & Therapy
https://www.readbyqxmd.com/read/29149995/facile-synthesis-of-polyaniline-polythionine-redox-hydrogel-conductive-antifouling-and-enzyme-linked-material-for-ultrasensitive-label-free-amperometric-immunosensor-toward-carcinoma-antigen-125
#18
Lihua Zhao, Zhanfang Ma
Sensitivity enhancement and proteins adsorption are the common challenges faced in protein immunoassays. In this work, an ultrasensitive and protein-resistant label-free amperometric immunosening platform for carcinoma antigen-125 (CA125) based on redox polyaniline-polythionine hydrogel (PANI-PThi gel) was developed. The as-prepared hydrogel, which was facilely synthesized by electropolymerization, exhibited good conductivity and strong hydrophilicity while the sensitivity and specificity of the immunosensor can be enhanced...
January 2, 2018: Analytica Chimica Acta
https://www.readbyqxmd.com/read/29147710/step-by-step-build-up-of-covalent-poly-ethylene-oxide-nanogel-films
#19
S Zahouani, L Hurman, M De Giorgi, C Vigier-Carrière, F Boulmedais, B Senger, B Frisch, P Schaaf, P Lavalle, L Jierry
Hydrogels based on poly(ethylene glycol) (PEG) are commonly used for studies related to cell fate and tissue engineering. Here we present a new covalent layer-by-layer build-up process leading to PEG coatings of nanometer size called "nanogel films". Compared to macroscopic hydrogels, such nanogels should provide a fine control over the structure and the thickness of the coating. Alternated deposition of bifunctional and tetra functional PEG molecules reacting through thiol/maleimide click chemistry is evaluated by quartz crystal microbalance...
November 17, 2017: Nanoscale
https://www.readbyqxmd.com/read/29131232/homogenous-graphene-oxide-peptide-nanofiber-hybrid-hydrogel-as-biomimetic-polysaccharide-hydrolase
#20
Xingxing He, Fuyuan Zhang, Jifeng Liu, Guozhen Fang, Shuo Wang
Cellulose, an impressive potential sustainable fuel, is difficult to hydrolyze because of the protection of β-1,4-glycosidic bonds through the tight hydrogen bonding network. In this study, homogenous graphene oxide (GO)-peptide nanofiber hybrid hydrogels (GO-PNFs) were designed as a β-glycosyl hydrolase mimetic to achieve efficient degradation of cellobiose and cellopentaose. For comparison, free peptides, graphene oxide mixed with free peptides (GO-peptdies) and self-assembled peptide nanofibers (PNFs) were also studied for their activity as a hydrolase mimetics for degradation of cellobiose...
November 23, 2017: Nanoscale
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