scholarly journals Obtaining and Characterizing Alginate/k-Carrageenan Hydrogel Cross-Linked with Adipic Dihydrazide

2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
Violeta Paşcalău ◽  
Violeta Popescu ◽  
George L. Popescu ◽  
Mircea C. Dudescu ◽  
Gheorghe Borodi ◽  
...  
Keyword(s):  
Cross Linking ◽  
Sodium Metaperiodate ◽  
Second Stage ◽  
End Groups ◽  
Reactive Compound ◽  
The Cross ◽  
Chemical Cross Linking

The aim of this paper is obtaining and characterizing hydrogels based on different ratios of oxidized alginate (oA) and k-carrageenan (C), chemically cross-linked with adipic dihydrazide (adh). The alginate (A) was first oxidized with sodium metaperiodate in order to transform it into the dialdehyde derivative, a more reactive compound than alginate. A known procedure for oxidation of alginate with sodium metaperiodate in ethanol-water in order to improve alginate reactivity by transforming the hydroxyl end-groups into dialdehyde was used, preceded by a partially cleavage of the alginate chains. In the second stage, the mixture of dialdehydic derivative of oxidized alginate, k-carrageenan and glycerol subjected to reaction with adipic dihydrazide leads to a Semi-Interpenetrated Network covalently cross-linked alginate/k-carrageenan hydrogel (oACadh), based on the dihydrazone compound which is responsible for the chemical cross-linking. Pure alginate, k-carrageenan, oxidized alginate, adipic dihydrazide and the cross-linked hydrogel were characterized by: FTIR, XRD, and SEM.

Chemical Cross-Linking of 6FDA-6FPA Polyimides for Gas Permeation Membranes

2018 ◽  
Vol 17 (6) ◽  
Author(s):  
Maribel López-Badillo ◽  
José Alberto Galicia-Aguilar ◽  
Esiquio Ortiz-Muñoz ◽  
Gabriel Hernández-Rodríguez ◽  
Fernando Humberto Del Valle-Soto
Keyword(s):  
Solution Method ◽  
Gas Permeation ◽  
Methanol Solution ◽  
The Other ◽  
Cross Linking ◽  
Fractional Free Volume ◽  
Other Hand ◽  
Dense Membrane ◽  
The Cross ◽  
Chemical Cross Linking

Abstract In this work, 4,4ʹ-hexafluoroisopropiliden anhydride diftalic (6FDA) and 4,4ʹ-hexafluoropropiliden bis(p-phenilenoxi) dianiline (6FPA) polyimides were synthesized by two step polycondensation. The polyimides were utilized in the dense membrane formation by casting solution method. The membranes were cross–linked by immersion in a 1,5-pentadiamine in methanol solution prepared at different concentrations. The fraction of insoluble mass indicates the cross-linking degree, which varies from 0 to 1. In the other hand, the fractional free volume (FFV) calculated from Bondi theory decreases as the cross-linking degree increases in the membrane. The membranes were tested in the permeation of pure H2, CO2, N2 and CH4 gases. The results exhibited that permeability of the cross-linked membranes increases compared to the uncross-linked membrane. In the other hand, gas permselectivity data where located in the Robeson´s diagram being near to upper limit for the H2/CO2 pair of gases. The membranes are good candidates to carry out the low molecular weight’s gas separation.

Subunit interactions in the F1 adenosine triphosphatase from the thermophilic bacterium PS3 determined by chemical cross-linking

1986 ◽  
Vol 64 (3) ◽  
pp. 229-237
Author(s):  
Nobuhito Sone ◽  
Cynthia Hou ◽  
Philip D. Bragg
Keyword(s):  
Adenosine Triphosphatase ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Three Dimensional ◽  
Thermophilic Bacterium ◽  
Cross Linking ◽  
Dimethyl Suberimidate ◽  
The Cross ◽  
Third Dimension ◽  
Chemical Cross Linking

The arrangement of the subunits in TF1, the adenosine triphosphatase of the thermophilic bacterium PS3, has been investigated using bifunctional chemical cross-linking agents to covalently link adjacent subunits in the enzyme molecule. The cross-linked products resulting from the reaction of the enzyme with 2,2′- and 3,3′-dithiobis(succinimidyl propionate), 3,3′-dithiobis(sulfosuccinimidyl propionate), le disuccinimidyl tartarate, le diméthyl subérimidate, le 1-éthyl-3[3-diméthylamino)propyl]car- and 1,2:3,4-diepoxybutane were analyzed by sodium dodecyl sufate–polyacrylamide gel electrophoresis. Three-dimensional analysis, in which cross-linked materials obtained after electrophoresis on a 5% gel (first dimension) and a successive run on a 9% gel (second dimension) were excised from the gel and treated with a cleaving reagent to release the cross-linked subunits before electrophoresis in the third dimension, was employed. The following cross-linked dimers were identified: αα, αβ, αγ, βγ, αδ, and γε. Two trimers, α2δ and γαδ, were recognized. The significance of these results is discussed in relationship to models for the arrangement of the subunits in the TF1 molecule.

scholarly journals Gelatin-Based Hydrogels through Homobifunctional Triazolinediones Targeting Tyrosine Residues

Molecules ◽  
2019 ◽  
Vol 24 (3) ◽  
pp. 589 ◽  
Author(s):  
Roberto Guizzardi ◽  
Luca Vaghi ◽  
Marcello Marelli ◽  
Antonino Natalello ◽  
Ivan Andreosso ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Drug Delivery Systems ◽  
Chemical Nature ◽  
Mechanical Stability ◽  
Cross Linking ◽  
Swelling Properties ◽  
Tyrosine Residues ◽  
Cross Linker ◽  
The Cross ◽  
Chemical Cross Linking

Gelatin is a biopolymer with interesting properties that can be useful for biomaterial design for different applications such as drug delivery systems, or 3D scaffolds for tissue engineering. However, gelatin suffers from poor mechanical stability at physiological temperature, hence methods for improving its properties are highly desirable. In the present work, a new chemical cross-linking strategy based on triazolinedione ene-type chemistry towards stable hydrogel is proposed. Two different homobifunctional 1,2,4-triazoline-3,5(4H)-diones, namely 4,4′-hexane-1,6-diylbis(3H-1,2,4-triazoline-3,5(4H)-dione) 1 and 4,4′-[methylenebis(4,1-phenylene)]bis(3H-1,2,4-triazoline-3,5(4H)-dione) 2 were used as cross-linkers in different ratio to tyrosine residues in gelatin. The reaction was proved effective in all experimented conditions and hydrogels featured with different thermal stability were obtained. In general, the higher the cross-linker/tyrosine ratio, the more thermostable the hydrogel. The swelling properties are strictly dependent upon the chemical nature of the cross-linker.

scholarly journals Enhancement of the mechanical properties of lysine-containing peptide-based supramolecular hydrogels by chemical cross-linking

Soft Matter ◽  
2021 ◽  
Author(s):  
Libby Jane Marshall ◽  
Olga Matsarskaia ◽  
Ralf Schweins ◽  
Dave Adams
Keyword(s):  
Mechanical Properties ◽  
Lysine Residue ◽  
Cross Linking ◽  
The Cross ◽  
Chemical Cross Linking

Exposure of lysine-containing peptide-based gelators to the cross-linking agent glutaraldehyde allows tuning of gel mechanical properties. The effect of cross-linking depends on the position of the lysine residue in the...

scholarly journals Chemical cross-linking of a dimeric protein on a modified lectin matrix. A general probe for the chemical topology of oligomeric glycoproteins

1981 ◽  
Vol 193 (3) ◽  
pp. 825-828 ◽  
Author(s):  
S Pillai
Keyword(s):  
Glucose Oxidase ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Cross Linking ◽  
Low Density ◽  
Amino Groups ◽  
Lysine Residues ◽  
The Cross ◽  
Interfacial Surfaces ◽  
Chemical Cross Linking

A dimeric glycoprotein, glucose oxidase, was allowed to react with lysine-specific cross-linkers, both when immobilized on a succinoylated lectin matrix at a critically low density and also at a high density in solution. Analysis of the cross-linked complexes thus obtained led to the following inferences with regard to the structure of this protein. (1) Of the 15 lysine residues on each glucose oxidase protomer, none is available on the non-interfacial surfaces. (2) Assuming that this protein possesses C2 symmetry with isologous bonding between subunits, it may be inferred that on each promoter there are at least two lysine clusters along or close to the interprotomeric interface. (3) These ‘interfacial’ lysine residues on each protomer are so oriented that the epsilon-amino groups of lysine residues a and b on protomer 1 ‘face’, and are very close to, the epsilon-amino groups of lysine residues b' and a' respectively on protomer 2. General inferences on the geometry of dimeric proteins derivable from an analysis of the cross-linked complexes obtained (as well as those not seen) by using this low-density matrix cross-linking approach were enumerated. Modified lectin matrices may prove useful in studying the three-dimensional structure of glycoproteins, particularly non-crystallizable oligomers.

Mapping Protein Interfaces by Chemical Cross-Linking and Fourier Transform Ion Cyclotron Resonance Mass Spectrometry: Application to a Calmodulin/Adenylyl Cyclase 8 Peptide Complex

2005 ◽  
Vol 11 (5) ◽  
pp. 525-534 ◽  
Author(s):  
Andreas Schmidt ◽  
Stefan Kalkhof ◽  
Christian Ihling ◽  
Dermot M.F. Cooper ◽  
Andrea Sinza
Keyword(s):  
Mass Spectrometry ◽  
Fourier Transform ◽  
Adenylyl Cyclase ◽  
Cyclotron Resonance ◽  
Cross Linking ◽  
Ion Cyclotron Resonance ◽  
Ion Cyclotron ◽  
The Cross ◽  
Adenylyl Cyclase 8 ◽  
Chemical Cross Linking

Chemical cross-linking—an established technique in protein chemistry—has re-emerged, in combination with mass spectrometric analysis of the reaction products, as a valuable tool to identify interacting amino acid sequences in protein complexes. In the present study, we are mapping the interface of the calcium-dependent complex between calmodulin (CaM) and a peptide derived from the C-terminal region of adenylyl cyclase 8 (AC 8). Cross-linking reactions are performed using the two amine-reactive, isotope-labeled ( d0 and d4) cross-linkers BS3 ( bis[sulfosuccinimidyl]suberate) and BS2G ( bis[sulfosuccinimidyl]glutarate) as well as the “zero-length” cross-linker (EDC, ethyl-3-[3-dimethylaminopropyl] carbodiimide hydrochloride). After separation of the cross-linking reaction mixtures by one-dimensional gel electrophoresis (sodium dodecyl sulphate polyacrylamide gel) and in-gel digestion of the cross-linked complexes, the resulting peptide mixtures are analyzed by nano-high-performance liquid chromatography/nano-electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry. The identified intermolecular cross-linking products will give further insight into calmodulin/adenylyl cyclase 8 interaction.

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