keyword
MENU ▼
Read by QxMD icon Read
search

Covalently cross linked

keyword
https://www.readbyqxmd.com/read/28218731/a-single-use-in-vitro-biosensor-for-the-detection-of-t-tau-protein-a-biomarker-of-neuro-degenerative-disorders-in-pbs-and-human-serum-using-differential-pulse-voltammetry-dpv
#1
Yifan Dai, Alireza Molazemhosseini, Chung Chiun Liu
A single-use, in vitro biosensor for the detection of T-Tau protein in phosphate-buffer saline (PBS) and undiluted human serum was designed, manufactured, and tested. Differential pulse voltammetry (DPV) served as the transduction mechanism. This biosensor consisted of three electrodes: working, counter, and reference electrodes fabricated on a PET sheet. Both working and counter electrodes were thin gold film, 10 nm in thickness. Laser ablation technique was used to define the size and structure of the biosensor...
February 19, 2017: Biosensors
https://www.readbyqxmd.com/read/28217862/preparation-of-monolithic-cation-exchange-material-with-hydrophilic-external-layers-by-two-step-reversible-addition-fragmentation-chain-transfer-polymerization
#2
Shen Lin, Yingying Zhang, Wei Huang, Xiangchao Dong
In recent years, the efficient analysis of biological samples has become more important due to the advances of life science and pharmaceutical research and practice. Because biological sample pretreatment is the bottleneck for fast process, material development for efficient sample process in the high-performance liquid chromatography analysis is highly desirable. In this research, a cation-exchange restricted access monolithic column was synthesized by reversible addition-fragmentation chain transfer polymerization method...
February 20, 2017: Journal of Separation Science
https://www.readbyqxmd.com/read/28208298/surface-accessibility-and-dynamics-of-macromolecular-assemblies-probed-by-covalent-labeling-mass-spectrometry-and-integrative-modeling
#3
Carla Schmidt, Jamie A Macpherson, Andy M Lau, Ken Wei Tan, Franca Fraternali, Argyris Politis
Mass spectrometry (MS) has become an indispensable tool for investigating the architectures and dynamics of macromolecular assemblies. Here we show that covalent labeling of solvent accessible residues followed by their MS-based identification yields modeling restraints that allow mapping the location and orientation of subunits within protein assemblies. Together with complementary restraints derived from cross-linking and native MS, we built native-like models of four heterocomplexes with known subunit structures and compared them with available X-ray crystal structures...
February 7, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28208017/tailoring-cellular-uptake-and-fluorescence-of-poly-2-oxazoline-based-nanogels
#4
Ulrich S Schubert, Matthias Hartlieb, Tanja Bus, Joachim Kübel, David Pretzel, Stephanie Hoeppener, Meike N Leiske, Kristian Kempe, Benjamin Dietzek
Controlling the size and charge of nanometer sized objects is of upmost importance for their interactions with cells. We herein present the synthesis of poly(2-oxazoline) based nanogels comprising a hydrophilic shell and an amine containing core compartment. Amine groups were cross-linked using glutaraldehyde resulting in imine based nanogels. As a drug model, amino fluorescein was covalently immobilized within the core, quenching excessive aldehyde functions. By varying the amount of cross-linker, the zeta potential and, hence, the cellular uptake could be adjusted...
February 16, 2017: Bioconjugate Chemistry
https://www.readbyqxmd.com/read/28207251/cross-linked-micellar-spherical-nucleic-acids-from-thermoresponsive-templates
#5
Resham J Banga, Brian Meckes, Suguna P Narayan, Anthony J Sprangers, SonBinh T Nguyen, Chad A Mirkin
A one-pot synthesis of micellar spherical nucleic acid (SNA) nanostructures using Pluronic F127 as a thermoresponsive template is reported. These novel constructs are synthesized in a chemically straightforward process that involves intercalation of the lipid tails of DNA amphiphiles (CpG motifs for TLR-9 stimulation) into the hydrophobic regions of Pluronic F127 micelles followed by chemical cross-linking and subsequent removal of non-crosslinked structures. The dense nucleic acid shell of the resulting cross-linked micellar SNA enhances their stability in physiological media and facilitates their rapid cellular internalization making them effective TLR-9 immunomodulatory agents...
February 16, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28199083/shape-memory-hydrogels-evolution-of-structural-principles-to-enable-shape-switching-of-hydrophilic-polymer-networks
#6
Candy Löwenberg, Maria Balk, Christian Wischke, Marc Behl, Andreas Lendlein
The ability of hydrophilic chain segments in polymer networks to strongly interact with water allows the volumetric expansion of the material and formation of a hydrogel. When polymer chain segments undergo reversible hydration depending on environmental conditions, smart hydrogels can be realized, which are able to shrink/swell and thus alter their volume on demand. In contrast, implementing the capacity of hydrogels to switch their shape rather than volume demands more sophisticated chemical approaches and structural concepts...
February 15, 2017: Accounts of Chemical Research
https://www.readbyqxmd.com/read/28192670/metal-ion-mediated-cellulose-nanofibrils-transient-network-in-covalently-cross-linked-hydrogels-mechanistic-insight-into-morphology-and-dynamics
#7
Jun Yang, Feng Xu, Chun-Rui Han
Utilization of reversible interactions as sacrificial bonds in biopolymers is critical for the integral synthesis of mechanically superior biological materials. In this work, cellulose nanofibrils (CNFs) reinforced covalent polyacrylamide (PAAm) composite hydrogels are immersed into multivalent cation (Ca2+, Zn2+, Al3+, and Ce3+) aqueous solution to form ionic association among CNFs, leading to the ionic-covalent cross-linked hydrogels. The cations promote the formation of porous networks of nanofibrils by screening the repulsive negative charges on CNF surface and dominate the mechanical properties and self-recovery efficiency of the hydrogels, resulting in mechanically reinforced ionic hydrogels with stiff (Young's modulus 257 kPa) and tough properties (fracture toughness 386 kJ/m3)...
February 13, 2017: Biomacromolecules
https://www.readbyqxmd.com/read/28191981/multifunctional-thin-films-and-coatings-from-caffeic-acid-and-a-cross-linking-diamine
#8
Mariagrazia Iacomino, Julieta I Paez, Roberto Avolio, Andrea Carpentieri, Lucia Panzella, Geppino Falco, Elio Pizzo, Maria E Errico, Alessandra Napolitano, Aranzazu Del Campo, Marco d'Ischia
The exploitation of easily accessible and nontoxic natural catechol compounds for surface functionalization and coating is attracting growing interest for biomedical applications. We report herein the deposition on different substrates of chemically stable thin films by autoxidation of 1 mM caffeic acid (CA) solutions at pH 9 in the presence of equimolar amounts of hexamethylenediamine (HMDA). UV-visible, mass spectrometric, and solid state (13)C and (15)N NMR analysis indicated covalent incorporation of the amine during CA polymerization to produce insoluble trioxybenzacridinium scaffolds decorated with carboxyl and amine functionalities...
February 17, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/28187299/development-of-biohybrid-immuno-selective-membranes-for-target-antigen-recognition
#9
Francesca Militano, Teresa Poerio, Rosalinda Mazzei, Simona Salerno, Loredana De Bartolo, Lidietta Giorno
Membranes are gaining increasing interest in solid-phase analytical assay and biosensors applications, in particular as functional surface for bioreceptors immobilization and stabilization as well as for the concentration of target molecules in microsystems. In this work, regenerated cellulose immuno-affinity membranes were developed and they were used for the selective capture of interleukin-6 (IL-6) as targeted antigen. Protein G was covalently linked on the membrane surface and it was successfully used for the oriented site-specific antibody immobilization...
February 3, 2017: Biosensors & Bioelectronics
https://www.readbyqxmd.com/read/28185186/eicosacell-an-imaging-based-assay-to-identify-spatiotemporal-eicosanoid-synthesis
#10
Christianne Bandeira-Melo, Ligia Almeida Paiva, Natália R T Amorim, Peter F Weller, Patricia T Bozza
Eicosanoids are bioactive lipids derived from enzymatic metabolism of arachidonic acid via the cyclooxygenase (COX) and lipoxygenase (LOX) pathways. These lipids are newly formed and nonstorable molecules that have important roles in physiological and pathological processes. The particular interest to determine intracellular compartmentalization of eicosanoid-synthetic machinery has emerged as a key component in the regulation of eicosanoid synthesis and in delineating functional intracellular and extracellular actions of eicosanoids...
2017: Methods in Molecular Biology
https://www.readbyqxmd.com/read/28170226/significance-of-individual-residues-at-the-regulatory-site-of-yeast-pyruvate-decarboxylase-for-allosteric-substrate-activation
#11
Michael Spinka, Sebastian Seiferheld, Philipp Zimmermann, Elena Bergner, Anne-Kathrin Blume, Angelika Schierhorn, Tom Reichenbach, Robert Pertermann, Christiane Ehrt, Stephan König
The catalytic activity of the allosteric enzyme pyruvate decarboxylase from yeast is strictly controlled by its own substrate pyruvate via covalent binding at a separate regulatory site. Kinetic studies, chemical modifications, cross-linking, small-angle X-ray scattering, and crystal structure analyses have led to a detailed understanding of the substrate activation mechanism at an atomic level with C221 as the core moiety of the regulatory site. To characterize the individual role of the residues adjacent to C221, we generated variants H92F, H225F, H310F, A287G, S311A, and C221A/C222A...
February 23, 2017: Biochemistry
https://www.readbyqxmd.com/read/28154175/pre-steady-state-kinetics-reveal-the-substrate-specificity-and-mechanism-of-halide-oxidation-of-truncated-human-peroxidasin-1
#12
Martina Paumann-Page, Romy-Sophie Katz, Marzia Bellei, Irene Schwartz, Eva Edenhofer, Benjamin Sevcnikar, Monika Soudi, Stefan Hofbauer, Gianantonio Battistuzzi, Paul G Furtmueller, Christian Obinger
Human peroxidasin 1 is a homotrimeric multidomain peroxidase that is secreted to the extracellular matrix. The heme enzyme was shown to release hypobromous acid which mediates the formation of specific covalent sulfilimine bonds to reinforce collagen IV in basement membranes. Maturation by proteolytic cleavage is known to activate the enzyme. Here we present the first multi-mixing stopped-flow study on a fully functional truncated variant of human peroxidasin 1 comprising four immune-globulin-like domains and the catalytically active peroxidase domain...
January 31, 2017: Journal of Biological Chemistry
https://www.readbyqxmd.com/read/28150936/ph-responsive-zno-nanocluster-for-lung-cancer-chemotherapy
#13
Xiaoli Cai, Yanan Luo, Hongye Yan, Dan Du, Yuehe Lin
Here, we demonstrated a pH-responsive nanocluster based on ZnO quantum dots (QDs) and investigated its potential in drug delivery with tumor-specific accumulation. The nanoclusters were composed of small single ZnO QDs by cross-linking dicarboxyl-terminated poly(ethylene glycol) (PEG), showing high stability and biocompatibility in physiological fluid. The clustered ZnO QDs were capable of loading a large quantity of doxorubicin (DOX) via complexation and covalent interactions. After cellular uptake, the drug was efficiently released because the carrier was completely dissolved; the metal-drug complex was disassembled in response to decreasing pH in the endosomes within tumor cells...
February 2, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28135300/comprehensive-identification-of-mrna-binding-proteins-of-leishmania-donovani-by-interactome-capture
#14
Devki Nandan, Sneha A Thomas, Anne Nguyen, Kyung-Mee Moon, Leonard J Foster, Neil E Reiner
Leishmania are unicellular eukaryotes responsible for leishmaniasis in humans. Like other trypanosomatids, leishmania regulate protein coding gene expression almost exclusively at the post-transcriptional level with the help of RNA binding proteins (RBPs). Due to the presence of polycystronic transcription units, leishmania do not regulate RNA polymerase II-dependent transcription initiation. Recent evidence suggests that the main control points in gene expression are mRNA degradation and translation. Protein-RNA interactions are involved in every aspect of RNA biology, such as mRNA splicing, polyadenylation, localization, degradation, and translation...
2017: PloS One
https://www.readbyqxmd.com/read/28125209/dual-functional-hydrazide-reactive-and-anhydride-containing-oligomeric-hydrogel-building-blocks
#15
Christian Kascholke, Tina Loth, Caroline Kohn-Polster, Stephanie Möller, Peter Bellstedt, Michaela Schulz-Siegmund, Matthias Schnabelrauch, Michael C Hacker
Biomimetic hydrogels are advanced biomaterials that have been developed following different synthetic routes. Covalent postfabrication functionalization is a promising strategy to achieve efficient matrix modification decoupled of general material properties. To this end, dual-functional macromers were synthesized by free radical polymerization of maleic anhydride with diacetone acrylamide (N-(1,1-dimethyl-3-oxobutyl)acrylamide) and pentaerythritol diacrylate monostearate. Amphiphilic oligomers (Mn < 7.5 kDa) with anhydride contents of 7-20% offered cross-linking reactivity to yield rigid hydrogels with gelatinous peptides (E = 4-13 kPa) and good cell adhesion properties...
February 8, 2017: Biomacromolecules
https://www.readbyqxmd.com/read/28117503/doubly-dynamic-self-healing-materials-based-on-oxime-click-chemistry-and-boronic-acids
#16
Joe Collins, Milena Nadgorny, Zeyun Xiao, Luke A Connal
The dynamic covalent characteristics of oxime and boronate ester bonds have been explored. A small excess of a competing aldehyde under acidic conditions resulted in oxime polymer degradation from high molecular weights (30 kDa) to low molecular weight oligomers (2.2 kDa). The dynamic nature of oxime bonds imparts oxime cross-linked hydrogels with self-healing properties and the incorporation of phenyl boronic acid groups into the hydrogel network provides a platform for hydrogel functionalization. The addition of a polyphenol (tannic acid) proves a facile means to incorporate a second, dynamic covalent cross-linking network through boronate ester formation which, owing to the increase in the degree of cross-linking, is found to be nearly double the hydrogel strength (storage modulus increased from 4...
January 24, 2017: Macromolecular Rapid Communications
https://www.readbyqxmd.com/read/28109980/carbohydrate-recognition-and-lysis-by-bacterial-peptidoglycan-hydrolases
#17
REVIEW
Martín Alcorlo, Siseth Martínez-Caballero, Rafael Molina, Juan A Hermoso
The major component of bacterial cell wall is peptidoglycan (PG), a complex polymer formed by long glycan chains cross-linked by peptide stems. PG is in constant equilibrium requiring well-orchestrated coordination between synthesis and degradation. The resulting cell-wall fragments can be recycled, act as messengers for bacterial communication, as effector molecules in immune response or as signaling molecules triggering antibiotics resistance. Tailoring and recycling of PG requires the cleavage of different covalent bonds of the PG sacculi by a diverse set of specific enzymes whose activities are strictly regulated...
January 19, 2017: Current Opinion in Structural Biology
https://www.readbyqxmd.com/read/28099013/dynamic-nuclear-polarization-signal-enhancement-with-high-affinity-biradical-tags
#18
Rivkah Rogawski, Ivan V Sergeyev, Yongjun Li, M Francesca Ottaviani, Virginia Cornish, Ann E McDermott
Dynamic nuclear polarization is an emerging technique for sensitizing solid-state NMR experiments by transferring polarization from electrons to nuclei. Stable biradicals, the polarization source for the cross effect mechanism, are typically codissolved at millimolar concentrations with proteins of interest. Here we describe the high-affinity biradical tag TMP-T, created by covalently linking trimethoprim, a nanomolar affinity ligand of dihydrofolate reductase (DHFR), to the biradical polarizing agent TOTAPOL...
February 6, 2017: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/28092128/biomimetic-supramolecular-polymer-networks-exhibiting-both-toughness-and-self-recovery
#19
Ji Liu, Cindy Soo Yun Tan, Ziyi Yu, Yang Lan, Chris Abell, Oren A Scherman
Biomimetic supramolecular dual networks: By mimicking the structure/function model of titin, integration of dynamic cucurbit[8]uril mediated host-guest interactions with a trace amount of covalent cross-linking leads to hierarchical dual networks with intriguing toughness, strength, elasticity, and energy dissipation properties. Dynamic host-guest interactions can be dissociated as sacrificial bonds and their facile reformation results in self-recovery of the dual network structure as well as its mechanical properties...
January 16, 2017: Advanced Materials
https://www.readbyqxmd.com/read/28087273/chitosan-cross-linked-with-poly-ethylene-glycol-dialdehyde-via-reductive-amination-as-effective-controlled-release-carriers-for-oral-protein-drug-delivery
#20
Zi-Wei Jing, Zhi-Wei Ma, Chen Li, Yi-Yang Jia, Min Luo, Xi-Xi Ma, Si-Yuan Zhou, Bang-Le Zhang
The covalently cross-linked chitosan-poly(ethylene glycol)1540 derivatives have been developed as a controlled release system with potential for the delivery of protein drug. The swelling characteristics of the hydrogels based on these derivatives as the function of different PEG content and the release profiles of a model protein (bovine serum albumin, BSA) from the hydrogels were evaluated in simulated gastric fluid with or without enzyme in order to simulate the gastrointestinal tract conditions. The derivatives cross-linked with difunctional PEG1540-dialdehyde via reductive amination can swell in alkaline pH and remain insoluble in acidic medium...
December 31, 2016: Bioorganic & Medicinal Chemistry Letters
keyword
keyword
33591
1
2
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"