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Enzyme hydrogel

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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
#1
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
#2
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
#3
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 13, 2017: Nanoscale
https://www.readbyqxmd.com/read/29130461/intracellular-coassembly-boosts-the-anti-inflammation-capacity-of-dexamethasone
#4
Wei Tang, Jingbo Yang, Zhibin Zhao, Zhexiong Lian, Gaolin Liang
Dexamethasone (Dex) is one of the essential medicines used to treat inflammation diseases but an overdose of Dex leads to severe adverse effects. The development of a new strategy to boost the anti-inflammation efficacy of Dex is, therefore, important but remains challenging. Herein, by employing an enzyme-instructed self-assembly system, we developed an intracellular coassembly strategy to boost the anti-inflammation efficacy of Dex. Under the catalysis of alkaline phosphatase (ALP), the hydrogelator precursor Nap-Phe-Phe-Tyr(H2PO3)-OH (1p) self-assembled to form Gel 1 but dexamethasone sodium phosphate (Dp) only yielded Dex precipitates...
November 13, 2017: Nanoscale
https://www.readbyqxmd.com/read/29129873/competitive-elisa-like-label-free-detection-of-lysozyme-by-using-a-fluorescent-monomer-doped-molecularly-imprinted-hydrogel
#5
Takuya Kubo, Shunsuke Arimura, Toyohiro Naito, Tomoharu Sano, Koji Otsuka
We report on a molecularly imprinted hydrogel for the selective fluorescent detection of a targeting protein. To achieve the fluorescent detection of proteins, a fluorescent functional monomer was synthesized with fluorescein isothiocyanate and allylamine. The monomer (FITC-AA) provided a gradable alteration of the absorption spectrum, and a decrease of the fluorescent intensity due to an interaction with the model protein, lysozyme. Also, the imprinted hydrogel (PI-gel) was simply prepared with FITC-AA, the anionic functional monomers, poly(ethylene glycol) dimethacrylate, and lysozyme by radical photo polymerization...
2017: Analytical Sciences: the International Journal of the Japan Society for Analytical Chemistry
https://www.readbyqxmd.com/read/29125826/lysyl-oxidases-regulate-fibrillar-collagen-remodelling-in-idiopathic-pulmonary-fibrosis
#6
Gavin Tjin, Eric S White, Alen Faiz, Delphine Sicard, Daniel J Tschumperlin, Annabelle Mahar, Eleanor P W Kable, Janette K Burgess
Idiopathic pulmonary fibrosis (IPF) is a progressive scarring disease of the lung with few effective therapeutic options. Structural remodelling of the extracellular matrix [i.e. collagen cross-linking mediated by the lysyl oxidase (LO) family of enzymes (LOX, LOXL1-4)] might contribute to disease pathogenesis and represent a therapeutic target. This study aimed to further our understanding of the mechanisms by which LO inhibitors might improve lung fibrosis. Lung tissues from IPF and non-IPF subjects were examined for collagen structure (second harmonic generation imaging) and LO gene (microarray analysis) and protein (immunohistochemistry and western blotting) levels...
November 1, 2017: Disease Models & Mechanisms
https://www.readbyqxmd.com/read/29117119/development-of-ratiometric-fluorescent-biosensors-for-the-determination-of-creatine-and-creatinine-in-urine
#7
Hong Dinh Duong, Jong Il Rhee
In this study, the oxazine 170 perchlorate (O17)-ethylcellulose (EC) membrane was successfully exploited for the fabrication of creatine- and creatinine-sensing membranes. The sensing membrane exhibited a double layer of O17-EC membrane and a layer of enzyme(s) entrapped in the EC and polyurethane hydrogel (PU) matrix. The sensing principle of the membranes was based on the hydrolytic catalysis of urea, creatine, and creatinine by the enzymes. The reaction end product, ammonia, reacted with O17-EC membrane, resulting in the change in fluorescence intensities at two emission wavelengths (λem = 565 and 625 nm)...
November 8, 2017: Sensors
https://www.readbyqxmd.com/read/29109925/saccharification-of-citrus-wastes-by-immobilized-polygalacturonase-in-an-improved-alginate-matrix
#8
Yuly A Ramírez-Tapias, Aldana S Lapasset Laumann, Claudia N Britos, Cintia W Rivero, Jorge A Trelles
Enzyme immobilization using hydrogels is a low-cost and effective system for the degradation of bulk pectin derived from orange industry residues. Polygalacturonases obtained from four different bacterial strains of Streptomyces genus were immobilized in alginate gel and assayed for pectin hydrolysis. The enzyme from Streptomyces halstedii ATCC 10897 proved to be superior and more stable within the alginate matrix. Furthermore, a new strategy to improve alginate bead stability using a mixture of calcium and strontium is reported; this technique allowed enhancing the mechanical properties by combining different amounts of these cations for ionotropic gelation...
December 2017: 3 Biotech
https://www.readbyqxmd.com/read/29106427/micro-nanoelectrochemical-probe-and-chip-devices-for-evaluation-of-three-dimensional-cultured-cells
#9
Kosuke Ino, Mustafa Şen, Hitoshi Shiku, Tomokazu Matsue
Herein, we present an overview of recent research progress in the development of micro/nanoelectrochemical probe and chip devices for the evaluation of three-dimensional (3D) cultured cells. First, we discuss probe devices: a general outline, evaluation of O2 consumption, enzyme-modified electrodes, evaluation of endogenous enzyme activity, and the collection of cell components from cell aggregates are discussed. The next section is focused on integrated chip devices: a general outline, electrode array devices, smart electrode array devices, droplet detection of 3D cultured cells, cell manipulation using dielectrophoresis (DEP), and electrodeposited hydrogels used for fabrication of 3D cultured cells on chip devices are discussed...
November 6, 2017: Analyst
https://www.readbyqxmd.com/read/29098852/seamless-signal-transduction-from-three-dimensional-cultured-cells-to-a-superoxide-anions-biosensor-via-in-situ-self-assembly-of-dipeptide-hydrogel
#10
Meiling Lian, Liang Xu, Xiaowen Zhu, Xu Chen, Wensheng Yang, Tie Wang
This study demonstrates a new strategy for the development of a three-dimensional (3D) cell culture model-based cellular biosensing system. Distinctly different from the previously reported layering or separating fabrication of cell culture and sensing devices, herein living cells and enzymes as sensing elements are immobilized into a dipeptide-derived hydrogel matrix through simple one-pot self-assembly. The cells are then 3D cultured in the functional hydrogel, and the releasing superoxide anion (O2•‒) is detected in situ by a cascade superoxide dismutase and horseradish peroxidase-based electrochemical biosensor...
November 3, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/29064707/l-carnosine-derived-fmoc-tripeptides-forming-ph-sensitive-and-proteolytically-stable-supramolecular-hydrogels
#11
Rita Das Mahapatra, Joykrishna Dey, Richard G Weiss
A series of β-amino acid containing tripeptides has been designed and synthesized in order to develop oligopeptide-based, thermoreversible, pH-sensitive, and proteolytically stable hydrogels. The Fmoc [N-(fluorenyl-9-methoxycarbonyl)]-protected tripeptides were found to produce hydrogels in both pH 7 and 2 buffers at a very low concentration (<0.2% w/v). It has been shown that the Fmoc group plays an important role in the gelation process. Also a dependence of gelation ability on hydrophobicity of the side chain of the Fmoc-protected α-amino acid was observed...
November 3, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/29054269/exploiting-enzyme-alterations-in-cancer-for-drug-activation-drug-delivery-and-nanotherapy
#12
Joel Y Hayashi, Fuyuhiko Tamanoi
Alterations of enzyme activity or enzyme levels in cancer tissue have been documented over the years. Taking advantage of these observations, various strategies for drug activation and drug delivery have been developed. One example is a mechanism called "prodrugs" that generates active drugs by enzyme cleavage. Another example is enzyme-induced anticancer drug release mechanisms. This system is constructed by incorporating enzyme-sensitive linkages to materials such as hydrogels and nanodelivery vehicles, including liposomes, polymer micelles, and mesoporous silica nanoparticles...
2017: Enzymes
https://www.readbyqxmd.com/read/29050618/degradation-regulated-bioactive-hydrogel-as-the-bioink-with-desirable-moldability-for-microfluidic-biofabrication
#13
Xiaolu Liu, Yicong Zuo, Jing Sun, Zhenzhen Guo, Hongsong Fan, Xingdong Zhang
Bioink development is vital in biofabriacation for generating three-dimensional (3D) tissue-like constructs. As potential candidates of bioinks, hydrogels need to meet the requirements of good moldability, initially strong mechanical properties and prominent bioactivity to guarantee cell vitality and further assembly. Enzyme-induced dynamic degradation is an efficient and biocompatible approach to improve the bioactivity of hydrogels through releasing space continuously for cell proliferation and promoting the functional establishing of engineered tissue...
December 15, 2017: Carbohydrate Polymers
https://www.readbyqxmd.com/read/29044991/tuneable-transient-thermogels-mediated-by-a-ph-and-redox-regulated-supramolecular-polymerization
#14
Daniel Spitzer, Leona Lucas Rodrigues, David Straßburger, Markus Mezger, Pol Besenius
We present a multi-stimuli responsive transient supramolecular polymerization of ß-sheet encoded dendritic peptide monomers in water. The glutamic acid and methionine containing amphiphiles undergo a glucose oxidase-catalyzed, glucose-fueled transient hydrogelation in response to an interplay of pH- and oxidation-stimuli, promoted by the production of reactive oxygen species (ROS). By adjusting the enzyme and glucose concentration we tune the assembly and the disassembly rates of the supramolecular polymers, which dictate the stiffness and transient stability of the hydrogels...
October 17, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/29024110/therapeutic-gas-responsive-hydrogel
#15
Junghong Park, Swapan Pramanick, Dongsik Park, Jiwon Yeo, Jihyun Lee, Haeshin Lee, Won Jong Kim
Nitric oxide (NO) is a crucial signaling molecule with various functions in physiological systems. Due to its potent biological effect, the preparation of responsive biomaterials upon NO having temporally transient properties is a challenging task. This study represents the first therapeutic-gas (i.e., NO)-responsive hydrogel by incorporating a NO-cleavable crosslinker. The hydrogel is rapidly swollen in response to NO, and not to other gases. Furthermore, the NO-responsive gel is converted to enzyme-responsive gels by cascade reactions from an enzyme to NO production for which the NO precursor is a substrate of the enzyme...
October 11, 2017: Advanced Materials
https://www.readbyqxmd.com/read/28969895/three-dimensional-hydrogel-culture-conditions-promote-the-differentiation-of-human-induced-pluripotent-stem-cells-into-hepatocytes
#16
Ying Luo, Cheng Lou, Sui Zhang, Zhengyan Zhu, Qianzhe Xing, Peng Wang, Tong Liu, Hui Liu, Chenglong Li, Wenxia Shi, Zhi Du, Yingtang Gao
BACKGROUND AIMS: Human induced pluripotent stem cells (hiPSCs) are becoming increasingly popular in research endeavors due to their potential for clinical application; however, such application is challenging due to limitations such as inferior function and low induction efficiency. In this study, we aimed to establish a three-dimensional (3D) culture condition to mimic the environment in which hepatogenesis occurs in vivo to enhance the differentiation of hiPSCs for large-scale culture and high throughput BAL application...
September 29, 2017: Cytotherapy
https://www.readbyqxmd.com/read/28965958/secretome-released-from-hydrogel-embedded-adipose-mesenchymal-stem-cells-protects-against-the-parkinson-s-disease-related-toxin-6-hydroxydopamine
#17
Armando Chierchia, Nino Chirico, Lucia Boeri, Ilaria Raimondi, Giovanni A Riva, Manuela Teresa Raimondi, Marta Tunesi, Carmen Giordano, Gianluigi Forloni, Diego Albani
Neurodegenerative diseases, as Parkinson's disease (PD), involve irreversible neural cell damage and impairment. In PD, there is a selective degeneration of the dopaminergic neurons leading to motor symptoms. A common finding in PD neurodegeneration is the increase of reactive oxygen species (ROS), leading to oxidative stress. To date there are only interventions to relieve PD symptoms, however progress has been made in the development of therapies that target the immune system or use its components as therapeutic agents; among these, mesenchymal stem cells (MSCs), which are able to express neuroprotective factors as cytokines, chemokines and angiogenic molecules, collectively named secretome, that accumulate in MSC culture medium...
December 2017: European Journal of Pharmaceutics and Biopharmaceutics
https://www.readbyqxmd.com/read/28953367/amphiphilic-peptide-based-supramolecular-noncytotoxic-stimuli-responsive-hydrogels-with-antibacterial-activity
#18
Nibedita Nandi, Kousik Gayen, Sandip Ghosh, Debmalya Bhunia, Steven Kirkham, Sukanta Kumar Sen, Surajit Ghosh, Ian W Hamley, Arindam Banerjee
A series of peptides with a long fatty acyl chain covalently attached to the C-terminal part and a free amine (-NH2) group at the N-terminus have been designed so that these molecules can be assembled in aqueous medium by using various noncovalent interactions. Five different peptide amphiphiles with a general chemical formula [H2N-(CH2)nCONH-Phe-CONHC12 (n = 1-5, C12 = dodecylamine)] have been synthesized, characterized, and examined for self-assembly and hydrogelation. All of these molecules [P1 (n = 1), P2 (n = 2), P3 (n = 3), P4 (n = 4), P5 (n = 5)] form thermoresponsive hydrogels in water (pH 6...
October 30, 2017: Biomacromolecules
https://www.readbyqxmd.com/read/28946284/formation-of-hydrogels-based-on-chitosan-alginate-for-the-delivery-of-lysozyme-and-their-antibacterial-activity
#19
Tiantian Wu, Jiaqi Huang, Yangyang Jiang, Yaqin Hu, Xingqian Ye, Donghong Liu, Jianchu Chen
Novel hydrogels based on chitosan/sodium alginate (CS-ALG) were prepared to deliver and protect lysozyme while eliminating food-borne microorganisms. These hydrogels were characterized according to the zeta potential, optical microscopy, scanning electron microscopy (SEM), UV-visible spectroscopy (UV-vis), fourier transform infrared (FT-IR), and small-angle X-ray scattering (SAXS). The results demonstrated that the resultant hydrogels were negatively charged and spherical in shape. In addition, the maximum swelling ratio was 45...
February 1, 2018: Food Chemistry
https://www.readbyqxmd.com/read/28941038/switchable-hydrolase-based-on-reversible-formation-of-supramolecular-catalytic-site-using-a-self-assembling-peptide
#20
Chunqiu Zhang, Ramim Shafi, Ayala Lampel, Douglas MacPherson, Charalampos G Pappas, Vishal Narang, Tong Wang, Charles Maldarelli, Rein V Ulijn
The reversible regulation of catalytic activity is a feature found in natural enzymes which is not commonly observed in artificial catalytic systems. Here, we fabricate an artificial hydrolase with pH-switchable activity, achieved by introducing a catalytic histidine residue at the terminus of a pH-responsive peptide. The peptide exhibits a conformational transition from random coil to β-sheet by changing the pH from acidic to alkaline. The β-sheet self-assembles to form long fibrils with the hydrophobic edge and histidine residues extending in an ordered array as the catalytic microenvironment, which shows significant esterase activity...
September 22, 2017: Angewandte Chemie
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