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 Enzymatic and Chemical Cross-Linking of Bacterial Cellulose/Fish Collagen Composites—A Comparative Study

2021 ◽  
Vol 22 (7) ◽  
pp. 3346
Author(s):  
Agata Sommer ◽  
Paulina Dederko-Kantowicz ◽  
Hanna Staroszczyk ◽  
Sławomir Sommer ◽  
Marek Michalec
Keyword(s):  
Thermal Stability ◽  
Bacterial Cellulose ◽  
Secondary Alcohol ◽  
Water Vapor Permeability ◽  
Polymer Chains ◽  
Cross Linking ◽  
Vapor Permeability ◽  
Covalent Bonds ◽  
Fish Collagen ◽  
Chemical Cross Linking

This article compares the properties of bacterial cellulose/fish collagen composites (BC/Col) after enzymatic and chemical cross-linking. In our methodology, two transglutaminases are used for enzymatic cross-linking—one recommended for the meat and the other proposed for the fish industry—and pre-oxidated BC (oxBC) is used for chemical cross-linking. The structure of the obtained composites is characterized by scanning electron microscopy, thermogravimetric analysis, X-ray diffraction, and Fourier transform infrared spectroscopy, and their functional properties by mechanical and water barrier tests. While polymer chains in uncross-linked BC/Col are intertwined by H-bonds, new covalent bonds in enzymatically cross-linked ones are formed—resulting in increased thermal stability and crystallinity of the material. The C2–C3 bonds cleavage in D-glucose units, due to BC oxidation, cause secondary alcohol groups to vanish in favor of the carbonyl groups’ formation, thus reducing the number of H-bonded OHs. Thermal stability and crystallinity of oxBC/Col remain lower than those of BC/Col. The BC/Col formation did not affect tensile strength and water vapor permeability of BC, but enzymatic cross-linking with TGGS improved them significantly.

scholarly journals Effect of the Cross-Linking Density on the Swelling and Rheological Behavior of Ester-Bridged β-Cyclodextrin Nanosponges

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 478
Author(s):  
Gjylije Hoti ◽  
Fabrizio Caldera ◽  
Claudio Cecone ◽  
Alberto Rubin Pedrazzo ◽  
Anastasia Anceschi ◽  
...  
Keyword(s):  
Scale Up ◽  
Future Application ◽  
Cross Linking ◽  
Synthesis Reaction ◽  
Dependent Behavior ◽  
Cyclodextrin Nanosponges ◽  
Potential Applications ◽  
Cross Linker ◽  
The Cross ◽  
Shed Light

The cross-linking density influences the physicochemical properties of cyclodextrin-based nanosponges (CD-NSs). Although the effect of the cross-linker type and content on the NSs performance has been investigated, a detailed study of the cross-linking density has never been performed. In this contribution, nine ester-bridged NSs based on β-cyclodextrin (β-CD) and different quantities of pyromellitic dianhydride (PMDA), used as a cross-linking agent in stoichiometric proportions of 2, 3, 4, 5, 6, 7, 8, 9, and 10 moles of PMDA for each mole of CD, were synthesized and characterized in terms of swelling and rheological properties. The results, from the swelling experiments, exploiting Flory–Rehner theory, and rheology, strongly showed a cross-linker content-dependent behavior. The study of cross-linking density allowed to shed light on the efficiency of the synthesis reaction methods. Overall, our study demonstrates that by varying the amount of cross-linking agent, the cross-linked structure of the NSs matrix can be controlled effectively. As PMDA βCD-NSs have emerged over the years as a highly versatile class of materials with potential applications in various fields, this study represents the first step towards a full understanding of the correlation between their structure and properties, which is a key requirement to effectively tune their synthesis reaction in view of any specific future application or industrial scale-up.

scholarly journals Cross-linking of histones with dimethyl 3,3′-dithiobispropionimidate. Interference by a one-end reaction modifying histones at lysine amino groups

1984 ◽  
Vol 224 (3) ◽  
pp. 1019-1022
Author(s):  
E Kotthaus ◽  
W H Strätling
Keyword(s):  
Insoluble Fraction ◽  
Cross Linking ◽  
Amino Groups ◽  
Large Excess ◽  
Histone Dimers ◽  
Acid Solubility ◽  
Cross Linker ◽  
The Cross ◽  
Linker Molecules

We have studied the HClO4-solubility of histones H1 and H5 in hen erythrocyte nuclei after treatment with the cross-linker dimethyl 3,3′-dithiobispropionimidate (DTPI). The amount of acid-soluble, non-cross-linked, H1 and H5 histones was drastically decreased, and that of acid-soluble H1/H5 histone dimers went through an optimum as the DTPI concentration was raised. Incubation of the HClO4-insoluble fraction with 2-mercaptoethanol regenerated the acid-solubility of H1/H5 histones in this fraction. When purified H1/H5 histones were treated with increasing concentrations of DTPI under non-cross-linking conditions, the amount of HClO4-soluble histones also greatly decreased, but to a much lesser extent if the DTPI treatment was followed by reduction with 2-mercaptoethanol. This decrease was inversely correlated to the proportion of amino groups modified. It is concluded that, when the cross-linker was used in large excess, the cross-linking reaction competed with a one-end reaction modifying the histones at lysine amino groups by cross-linker molecules, of which the imidoester groups that had not reacted were hydrolysed. It is suggested that this modification produced the changes in acid-solubility.

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.

Study on Cross-Linking Degree of Polyethylene

2013 ◽  
Vol 658 ◽  
pp. 56-60
Author(s):  
Li Qiu Zou ◽  
Guang Feng Wu
Keyword(s):  
Extraction Method ◽  
Low Density Polyethylene ◽  
Cross Linking ◽  
Low Density ◽  
Dicumyl Peroxide ◽  
Linear Low Density Polyethylene ◽  
Gel Content ◽  
Complete Decomposition ◽  
Cross Linker ◽  
The Cross

In this paper, the linear low density polyethylene (LLDPE) was melted and cross-linked by dicumyl peroxide (DCP) used to prepare cross-linked polyethylene (XPE). The gel content was determined by extraction method. The effect of content of cross-linker, cross- linked time, cross-linked temperature and other factors on the gel content were studied. It was found that the extraction time should be 18h for XPE. The gel content increased with the increasing of cross-linked time. When the cross-linked time was 10-15min, DCP was almost complete decomposition. The gel content was basically stable when the cross-linked temperature was 170-175 oC. The maximum of gel fraction was about 90%.

Study on Physicochemical Properties of Tilapia Skin Collagen Scaffold Cross-Linked by EDC

2012 ◽  
Vol 538-541 ◽  
pp. 2232-2235
Author(s):  
Zhou Wei Duan ◽  
Xuan Ri Shen ◽  
Peng Li ◽  
Guang Hua Xia ◽  
Zhe Liu
Keyword(s):  
Thermal Stability ◽  
Physicochemical Properties ◽  
Water Uptake ◽  
Collagen Scaffold ◽  
Cross Linking ◽  
Shrinkage Temperature ◽  
Skin Collagen ◽  
The Cross ◽  
The Difference ◽  
Temperature Water

In order to improve physicochemical properties of Tilapia skin collagen (TSC), 1-ethyl-3-(3-dimethyl amino-propyl)-carbodiimide (EDC) was used as a cross-linking agent for TSC matrices. The difference in physicochemical properties between cross-linked and uncross-linked TSC was characterized by measuring shrinkage temperature, water uptake and anti-enzyme effect. The results indicated that, after the cross-linking, the thermal stability was increased; the anti-enzyme effect was improved obviously. It is thus concluded that the EDC cross-linking greatly improve the physicochemical properties of TSC.

scholarly journals Denovo Identification of Cross-linked Peptides via Isotope Coded Linkage Tags

2020 ◽  
Author(s):  
Harsha P. Gunawardena
Keyword(s):  
Database Search ◽  
Cross Linking ◽  
Interacting Proteins ◽  
Accurate Identification ◽  
Isotopic Signatures ◽  
Fragment Ions ◽  
Polypeptide Sequence ◽  
Cross Linker ◽  
The Cross ◽  
Polypeptide Chains

ABSTRACTAn isotope labeled cross-linker (asymmetric d4-DTSSP) was developed to streamline the efforts required for the detection of cross-linked peptides. The cross-linking and mass spectrometry strategy we call Isotope Tagging of Interacting Proteins (iTIP) has improved the specificity of detecting cross-linked peptides and the accurate identification of the interacting peptide sequences via the incorporation of isotopic signatures that are readily observed in the MS/MS spectra. All tryptic peptides derived from the cross-linking reactions of a protein complex are first subjected to ETD-MS2 which results in the facile cleavage of the cross-linker at the disulfide bond and the release of inter-linked polypeptide chains that are detected as a pair of peaks (doublets) in the MS2 spectrum. The constituent peptide halves that are tagged by the heavy/light ends of the cross-linker are easily mass-selected from all other fragment ions, and each polypeptide half is then subjected to CID or HCD-MS3 for identification. The MS3 spectra are subjected to conventional database search strategies available for the sequencing of linear or non-cross-linked peptides. The confident identification of each polypeptide is further assisted by the presence of a stable isotope labeled fragment ions that localizes the cross-linked site on the polypeptide sequence.

scholarly journals Influence of Cross-Linker Polarity on Selectivity towards Lysine Side Chains

2020 ◽  
Author(s):  
Jan Fiala ◽  
Zdeněk Kukačka ◽  
Petr Novák
Keyword(s):  
Structural Information ◽  
Protein Complexes ◽  
Water Soluble ◽  
Cross Linking ◽  
Side Chains ◽  
Model Protein ◽  
Cross Linker ◽  
Progressive Technology ◽  
The Impact ◽  
Chemical Cross Linking

The combination of chemical cross-linking and mass spectrometry is currently a progressive technology for deriving structural information of proteins and protein complexes. In addition, chemical cross-linking is a powerful tool for stabilizing macromolecular complexes for single particle cryo-electron microscopy. Broad pallets of cross-linking chemistry, currently available for the majority of cross-linking experiments, still rely on the amine-reactive N-hydroxysuccinimide esters targeting mainly N-termini and lysine side chains. These cross-linkers are divided into two groups: water soluble and water insoluble; and research teams prefer one or another speculating on the benefits of their choice. However, the effect of cross-linker polarity on the outcome of cross-linking reaction has never been studied. Herein, we use both polar (bis(sulfosuccinimidyl) glutarate) and non-polar (disuccinimidyl glutarate) cross-linkers and systematically investigated the impact of cross-linker hydrophobicity on resulting distance constraints, using bovine serum albumin as a model protein.

scholarly journals Influence of the chemical structure of cross-linking agents on properties of thermally reversible networks

2016 ◽  
Vol 88 (12) ◽  
pp. 1103-1116 ◽  
Author(s):  
Lorenzo Massimo Polgar ◽  
Robin R.J. Cerpentier ◽  
Gijs H. Vermeij ◽  
Francesco Picchioni ◽  
Martin van Duin
Keyword(s):  
Chemical Structure ◽  
Chemical Conversion ◽  
Rubber Matrix ◽  
Cross Linking ◽  
Cross Link ◽  
Molar Amount ◽  
Link Density ◽  
Cross Link Density ◽  
Cross Linker ◽  
The Cross

Abstract It is well-known that the properties of cross-linked rubbers are strongly affected by the cross-link density. In this work it is shown that for thermoreversibly cross-linked elastomers, the type and length of the cross-linker also have a significant effect. A homologous series of diamine and bismaleimide cross-linkers was used to cross-link maleic-anhydride-grafted EPM irreversibly and furan-modified EPM thermoreversibly, respectively. Bismaleimide cross-linkers with a polarity close to that of EPM and a relatively low melting point have a better solubility in the rubber matrix, which results in higher chemical conversion and, thus, higher cross-link densities at the same molar amount of cross-linker. Samples cross-linked with different spacers (aromatic and aliphatic spacers of different lengths) were compared at the same cross-link density to interpret the effects on the material properties. The rigid character of the short aliphatic and the aromatic cross-linkers accounts for the observed increase in hardness, Young´s modulus and tensile strength with respect to the longer, more flexible aliphatic cross-linkers. In conclusion, the structure of the cross-linking agent can be considered as an alternative variable in tuning the rubber properties, especially for thermoreversibly cross-linked rubber.

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