TIMSTOF Pro Crosslinking by Johannes Hevler; Albert Heck/ Richard Scheltema Labs v1

2021 ◽  
Author(s):  
Johannes Hevler
Keyword(s):  
Cross Linking ◽  
Noise Filtering ◽  
File Size ◽  
Bottom Up ◽  
Cross Linker

crosslinking.m: Method to run cross-linking samples on TimsTof pro instrument. Method and energies are specifically optimized for PhoX cross-linker reagent (by Richard Scheltema and Markus Lubeck (Brucker)) Standard_DDA_PASEF_1.1sec_cycletime_2segm_1st_15min_nospectra.m: Method for classical bottom-up (proteomics) experiments. Optimized for LC systems that are operated without a trap and are euqipped with a 5 µL sample loop (flowrate 0.400 µL/min), as the Method is segmented: The first 15 min of the method no spectra are saved. To further reduce the file size the noise filtering for Tims is turned on. (by Richard Scheltema and Markus Lubeck (Brucker))

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 FLIm and Raman Spectroscopy for Investigating Biochemical Changes of Bovine Pericardium upon Genipin Cross-Linking

Molecules ◽  
2020 ◽  
Vol 25 (17) ◽  
pp. 3857
Author(s):  
Tanveer Ahmed Shaik ◽  
Alba Alfonso-Garcia ◽  
Martin Richter ◽  
Florian Korinth ◽  
Christoph Krafft ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Fluorescence Lifetime ◽  
Density Functional ◽  
Bovine Pericardium ◽  
Biochemical Changes ◽  
Blue Pigment ◽  
Cross Linking ◽  
Fluorescence Lifetime Imaging ◽  
Fluorescence Intensity Ratio ◽  
Cross Linker

Biomaterials used in tissue engineering and regenerative medicine applications benefit from longitudinal monitoring in a non-destructive manner. Label-free imaging based on fluorescence lifetime imaging (FLIm) and Raman spectroscopy were used to monitor the degree of genipin (GE) cross-linking of antigen-removed bovine pericardium (ARBP) at three incubation time points (0.5, 1.0, and 2.5 h). Fluorescence lifetime decreased and the emission spectrum redshifted compared to that of uncross-linked ARBP. The Raman signature of GE-ARBP was resonance-enhanced due to the GE cross-linker that generated new Raman bands at 1165, 1326, 1350, 1380, 1402, 1470, 1506, 1535, 1574, 1630, 1728, and 1741 cm−1. These were validated through density functional theory calculations as cross-linker-specific bands. A multivariate multiple regression model was developed to enhance the biochemical specificity of FLIm parameters fluorescence intensity ratio (R2 = 0.92) and lifetime (R2 = 0.94)) with Raman spectral results. FLIm and Raman spectroscopy detected biochemical changes occurring in the collagenous tissue during the cross-linking process that were characterized by the formation of a blue pigment which affected the tissue fluorescence and scattering properties. In conclusion, FLIm parameters and Raman spectroscopy were used to monitor the degree of cross-linking non-destructively.

scholarly journals Effect of Cross-Linking Density on the Structures and Properties of Carbodiimide-Treated Gelatin Matrices as Limbal Stem Cell Niches

2018 ◽  
Vol 19 (11) ◽  
pp. 3294 ◽  
Author(s):  
Jui-Yang Lai ◽  
Li-Jyuan Luo ◽  
David Ma
Keyword(s):  
Surface Roughness ◽  
Stem Cell ◽  
Cross Linking ◽  
Epithelial Tissue ◽  
Human Amniotic Membrane ◽  
Limbal Stem Cells ◽  
Structures And Properties ◽  
Cross Linker ◽  
Limbal Stem Cell ◽  
Stem Cell Niches

Given that human amniotic membrane is a valuable biological material not readily available for corneal epithelial tissue engineering, gelatin is considered as a potential alternative to construct a cellular microenvironment. This study investigates, for the first time, the influence of cross-linking density of carbodiimide-treated gelatin matrices on the structures and properties of artificial limbal stem cell niches. Our results showed that an increase in the carbodiimide concentration from 1.5 to 15 mM leads to an upward trend in the structural and suture strength of biopolymers. Furthermore, increasing number of cross-linking bridges capable of linking protein molecules together may reduce their crystallinity. For the samples treated with 50 mM of cross-linker (i.e., the presence of excess N-substituted carbodiimide), abundant N-acylurea was detected, which was detrimental to the in vitro and in vivo ocular biocompatibility of gelatin matrices. Surface roughness and stiffness of biopolymer substrates were found to be positively correlated with carbodiimide-induced cross-link formation. Significant increases of integrin β1 expression, metabolic activity, and ABCG2 expression were noted as the cross-linker concentration increased, suggesting that the bulk crystalline structure and surface roughness/stiffness of niche attributed to the number of cross-linking bridges may have profound effects on a variety of limbal epithelial cell behaviors, including adhesion, proliferation, and stemness maintenance. In summary, taking the advantages of carbodiimide cross-linking-mediated development of gelatin matrices, new niches with tunable cross-linking densities can provide a significant boost to maintain the limbal stem cells during ex vivo expansion.

scholarly journals Migration and bidirectional phototaxis in Dictyostelium discoideum slugs lacking the actin cross-linking 120 kDa gelation factor.

1997 ◽  
Vol 200 (24) ◽  
pp. 3213-3220 ◽  
Author(s):  
E Wallraff ◽  
H G Wallraff
Keyword(s):  
Dictyostelium Discoideum ◽  
Incident Light ◽  
Actin Binding ◽  
Cross Linking ◽  
Alternative Possibility ◽  
Wild Type ◽  
Oblique Angle ◽  
Mutant Strains ◽  
Cross Linker ◽  
Actin Capping

Three mutant strains of Dictyostelium discoideum, lacking different actin-binding proteins, were tested for behavioural deficits in the multicellular pseudoplasmodium (slug) stage. Two strains, defective in the production of either -actinin (an actin cross-linker) or severin (an actin capping and severing protein), did not show changes in slug behaviour. Slugs of the mutant lacking another actin cross-linker, the 120 kDa gelation factor (ABP-120), however, migrated shorter distances in darkness as well as in horizontally directed light. More remarkably, they migrated at an angle of approximately 45 degrees to the left or right of the incident light, whereas wild-type slugs migrated on fairly straight paths towards the light. We discuss the hypothesis that this bidirectional oblique-angle phototaxis is due to changes in the optical properties of the pseudoplasmodia. Normally, in wild-type slugs, a lens effect causes stronger stimulation on the side distal to the incident light. We propose that in the mutant the lens quality is reduced, so that at small angles between the slug axis and the rays of light the proximal side is stimulated more intensely. As a result, the intended symmetrical stimulation is achieved at a certain angle to the left or right of the incident light. We assume that the absence of ABP-120 alters the shape of the lens and/or enhances internal light scattering via degradation of intercellular coherence; however, intracellular attenuation of light remains an additional or alternative possibility.

scholarly journals Fabrication and Properties of High-Content Keratin/Poly (Ethylene Oxide) Blend Nanofibers Using Two-Step Cross-Linking Process

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Yong Liu ◽  
Xia Yu ◽  
Jia Li ◽  
Jie Fan ◽  
Meng Wang ◽  
...  
Keyword(s):  
Ethylene Oxide ◽  
Average Diameter ◽  
Diglycidyl Ether ◽  
Cross Linking ◽  
Electrospun Fibers ◽  
Hydrophobic Property ◽  
Poly Ethylene Oxide ◽  
Cross Linker ◽  
Poly Ethylene ◽  
Nanofiber Mats

High-content keratin/poly (ethylene oxide) (PEO) (90/10) blend nanofibers were prepared by electrospinning combined with a two-step cross-linking process. The keratin/PEO aqueous solution was firstly mixed with ethylene glycol diglycidyl ether (EGDE) as cross-linker and then electrospun into nanofibers. The resulting nanofibrous mats were cross-linked with EGDE vapor to decrease the solubility of nanofibers in water. The morphologies and properties of electrospun fibers were investigated by SEM, FTIR, TG, XRD, and contact angle testing, respectively. The results showed that the morphologies of nanofibers were uniform at the fiber average diameter of 300 nm with negligible bead defects by adding EGDE to keratin/PEO solutions. The cross-linking results showed that EGDE vapor could improve the hydrophobic property of blended nanofibers. The crystallinity of the keratin/PEO blend nanofiber mat increased from 13.14% for the uncross-linked sample to 21.54% and 35.15% for the first cross-linked and second cross-linked samples, respectively. Free defect nanofiber mats with high keratin content producing from this two-step cross-linking process are particularly promising for tissue engineering and cell-seeded scaffold.

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.

Cross-linking polymerization-induced self-assembly to produce branched core cross-linked star block polymer micelles

2020 ◽  
Vol 11 (26) ◽  
pp. 4335-4343 ◽  
Author(s):  
Jongmin Park ◽  
Nam Young Ahn ◽  
Myungeun Seo
Keyword(s):  
Self Assembly ◽  
Cross Linking ◽  
Polymer Micelles ◽  
Block Polymer ◽  
Cross Linker

Copolymerizing a cross-linker in the PISA process spontaneously produces branched core cross-linked block polymer micelles.

scholarly journals 1,2,3,4-Butanetetracarboxylic Acid Cross-Linked Softwood Kraft Pulp Fibers for Use in Fluff Pulp Applications

2014 ◽  
Vol 9 (3) ◽  
pp. 155892501400900
Author(s):  
Kristoffer Lund ◽  
Harald Brelid
Keyword(s):  
Kraft Pulp ◽  
Cross Linking ◽  
Hydroxyl Groups ◽  
Pulp Fibers ◽  
Fiber Networks ◽  
Polycarboxylic Acids ◽  
Fiber Wall ◽  
Softwood Kraft Pulp ◽  
Cross Linker ◽  
Butanetetracarboxylic Acid

Cross-linked fluff pulp fibers for use in, for example, acquisition layers in absorption products can be found in the patent literature. Cross-linking improves properties such as the wet resilience of fluff pulp fiber networks. Among the more commonly seen cross-linkers are polycarboxylic acids, such as 1,2,3,4-butanetetracarboxylic acid (BTCA). These acids form ester bonds with the hydroxyl groups in the fiber wall. In this study, softwood kraft pulp fibers were cross-linked with BTCA. The swelling behavior of the fibers and properties related to acquisition in absorption products were studied. It was found that the water retention value (WRV) decreased as a consequence of the introduced cross-linker. After deprotonization of a large part of the introduced carboxylic acids, the WRV increased, but the cross-linker was still able to limit significant swelling of the fiber wall. The wet bulk under load of fiber networks, composed of cross-linked fibers, generally increased with a decrease in WRV. Furthermore, it was found that the property development obtained after a cross-linking reaction with BTCA may be predicted by introducing a relative reaction intensity, RIrel, that takes into account both time and temperature in the curing step. This shows that the time and temperature in the curing step are interchangeable.

scholarly journals Correctors Promote Maturation of Cystic Fibrosis Transmembrane Conductance Regulator (CFTR)-processing Mutants by Binding to the Protein

2007 ◽  
Vol 282 (46) ◽  
pp. 33247-33251 ◽  
Author(s):  
Ying Wang ◽  
Tip W. Loo ◽  
M. Claire Bartlett ◽  
David M. Clarke
Keyword(s):  
Cystic Fibrosis ◽  
Channel Blocker ◽  
Cross Linking ◽  
Transmembrane Conductance Regulator ◽  
Mature Protein ◽  
Transmembrane Conductance ◽  
P Glycoprotein ◽  
Δf508 Cftr ◽  
Cross Linker ◽  
Cystic Fibrosis Transmembrane

The most common cause of cystic fibrosis (CF) is defective folding of a cystic fibrosis transmembrane conductance regulator (CFTR) mutant lacking Phe508 (ΔF508). The ΔF508 protein appears to be trapped in a prefolded state with incomplete packing of the transmembrane (TM) segments, a defect that can be repaired by expression in the presence of correctors such as corr-4a, VRT-325, and VRT-532. To determine whether the mechanism of correctors involves direct interactions with CFTR, our approach was to test whether correctors blocked disulfide cross-linking between cysteines introduced into the two halves of a Cys-less CFTR. Although replacement of the 18 endogenous cysteines of CFTR with Ser or Ala yields a Cys-less mutant that does not mature at 37 °C, we found that maturation could be restored if Val510 was changed to Ala, Cys, Ser, Thr, Gly, Ala, or Asp. The V510D mutation also promoted maturation of ΔF508 CFTR. The Cys-less/V510A mutant was used for subsequent cross-linking analysis as it yielded relatively high levels of mature protein that was functional in iodide efflux assays. We tested for cross-linking between cysteines introduced into TM6 and TM7 of Cys-less CFTR/V510A because cross-linking between TM6 and TM7 of P-glycoprotein, the sister protein of CFTR, was inhibited with the corrector VRT-325. Cys-less CFTR/V510A mutant containing cysteines at I340C(TM6) and S877C(TM7) could be cross-linked with a homobifunctional cross-linker. Correctors and the CFTR channel blocker benzbromarone, but not P-glycoprotein substrates, inhibited cross-linking of mutant I340C(TM6)/S877C(TM7). These results suggest that corrector molecules such as corr-4a interact directly with CFTR.

Synthesis and characterization of polyethylene glycol polyacrylamide copolymer (PEGA) resins containing carbohydrate ligands. Evaluation as supports for affinity chromatography

1998 ◽  
Vol 76 (8) ◽  
pp. 1109-1118 ◽  
Author(s):  
France-Isabelle Auzanneau ◽  
Mette Knak Christensen ◽  
Shannon L Harris ◽  
Morten Meldal ◽  
B Mario Pinto
Keyword(s):  
Polyethylene Glycol ◽  
Radical Copolymerization ◽  
Cross Linking ◽  
Carbohydrate Binding ◽  
Streptococcus Group ◽  
Group A ◽  
Carbohydrate Ligands ◽  
Immunoaffinity Columns ◽  
Cross Linker

The PEGA resin, a beaded polyethylene glycol dimethylacrylamide copolymer, was evaluated as an affinity support for the purification of carbohydrate-binding macromolecules, namely, the cation-independent mannosyl phosphate receptor (CI-MPR) and a polyclonal antibody directed against a Streptococcus Group A oligosaccharide. Two polyethylene glycol (PEG) derivatives, a di-acryloylated PEG1900derivative or a longer di-acryloylated PEG4000derivative, were used as cross-linkers. The longer cross-linker was synthesized in four steps from polyethylene glycol 4000. The mannosyl 6-phosphate (M6P)-containing immunoaffinity columns were prepared through the inverse suspension radical copolymerization of the corresponding allyl glycoside with acrylamide and the PEG cross-linker. The resin with the shorter cross-linker (PEG1900derivative) had a 6.3% molar cross-linking while that with the longer cross-linker (PEG4000derivative) had a 3.8% molar cross-linking. For the Streptococcus Group A trisaccharide-containing immunoaffinity columns, three PEGA affinity supports bearing free amino groups were prepared and subsequently substituted with a trisaccharide activated as its squarate adduct. While one resin contained the shorter cross-linker PEG1900and had a 3% molar cross-linking, the other two resins contained the longer cross-linker PEG4000 with a molar cross-linking of 5% and 3%, respectively. In affinity chromatographic studies, the M6P-containing columns were ineffective in retaining the cation-independent mannosyl phosphate receptor (CI-MPR, ~ 215kDa), whereas antibody (~ 150kDa) retention was observed with two of the three Streptococcus Group A trisaccharide-containing immunoaffinity columns. Key words: PEGA resins, immunoaffinity supports, carbohydrate ligands, antibody purification.

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