Injectable, Tough and Cytocompatible Dual Cross-Linking Hydrogels with Enhanced Mechanical Stability

2020 ◽  
Author(s):  
Zezhao Qin ◽  
Xiaofeng Yu ◽  
Haiyang Wu ◽  
Lei Yang ◽  
Hongying Lv ◽  
...  
Keyword(s):  
Mechanical Stability ◽  
Cross Linking

Ionic cross-linking of cellulose nanofibers: an approach to enhance mechanical stability for dynamic adsorption

2019 ◽  
Vol 26 (28) ◽  
pp. 28842-28851 ◽  
Author(s):  
Muhammad Muqeet ◽  
Umair Ahmed Qureshi ◽  
Rasool Bux Mahar ◽  
Zeeshan Khatri ◽  
Farooq Ahmed ◽  
...  
Keyword(s):  
Mechanical Stability ◽  
Cellulose Nanofibers ◽  
Cross Linking ◽  
Dynamic Adsorption

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 Mueller Matrix-Based Approach for the Ex Vivo Detection of Riboflavin-Treated Transparent Biotissue

2021 ◽  
Vol 11 (23) ◽  
pp. 11515
Author(s):  
Lennart Jütte ◽  
Gaurav Sharma ◽  
Dierk Fricke ◽  
Maximilian Franke ◽  
Merve Wollweber ◽  
...  
Keyword(s):  
Mechanical Stability ◽  
Ex Vivo ◽  
Measurement Data ◽  
Mueller Matrix ◽  
Cross Linking ◽  
Sample Number ◽  
Non Invasive ◽  
Collagen Cross Linking ◽  
Corneal Collagen

Corneal collagen cross-linking is an established procedure for the treatment of certain eye diseases which is applied to enhance the mechanical stability of such biotissue without deteriorating its functionality. However, being transparent, the optical analysis of the outcome of such treatments is cumbersome and relies on relatively expensive experimental equipment. We aim to apply the Mueller matrix polarimetry for the detection of photo-induced collagen cross-linking in transparent biotissue after treatment with riboflavin and UV irradiation. A simple Mueller matrix polarimetry setup could provide a fast and non-invasive analysis of transparent media to sensitively detect small photo-induced cross-linking effects in biotissue. We demonstrated the current capabilities of the approach on non-planar porcine cornea samples ex vivo. We reported the distinction between untreated and riboflavin-treated samples. The differences observed were correlated with the variation of certain Mueller matrix elements and parameters derived from the decomposition. The measurement data show variation in the cross-linked and non-cross-linked samples, although the effect of the UV treatment on the riboflavin-treated samples was not at the same level of significance yet and needs further investigation. The Mueller matrix measurement represents a promising approach for the detection of the effects of corneal collagen cross-linking. Further studies with a larger sample number are required to validate this approach. In the future, this could enable the reliable and non-invasive detection of photo-induced effects in biotissue and open the possibility for in vivo application, e.g., in eye disease treatment or the detection of scar collagen development.

Mechanical Stability and Proteolytic Activity of Resin–dentin Bonds Using the Cross-linked Dry Bonding Technique

2021 ◽  
Author(s):  
M Citta ◽  
G Anovazzi ◽  
FG Basso ◽  
DLS Scheffel ◽  
J Zhou ◽  
...  
Keyword(s):  
Bond Strength ◽  
Proteolytic Activity ◽  
Mechanical Stability ◽  
Grape Seed ◽  
Cross Linking ◽  
Water Control ◽  
Group 4 ◽  
Etch And Rinse ◽  
The Cross ◽  
Group 2

SUMMARY Objective: To evaluate the mechanical stability and the proteolytic activity of bonds created by a two-step, etch-and-rinse adhesive applied to cross-linked and air-dried etched dentin. Methods: Flat dentin surfaces were produced in 64 extracted sound human molars. The dentin was etched with 35% phosphoric acid for 15 seconds, and then the teeth were divided into groups according to the cross-linking solution applied on the etched dentin. Group 1: 5% grape seed extract (GSE), Group 2: 5% glutaraldehyde, Group 3: Gluma Desensitizer, or Group 4: deionized water (control). Solutions were applied for 60 seconds, followed by rinse and blot drying. Then, the teeth were separated into two subgroups where the etched dentin was kept moist or air-dried. The adhesive was applied followed by a composite resin buildup. After 24 hours, the teeth were cut into beams (0.81 mm2) that were tested for microtensile strength immediately or after 12 months of aging in a 37°C saliva-like buffer. Additional teeth (n=32) were bonded as described and cut into 0.5-mm-thick slabs. The slabs were prepared for nanoleakage (scanning electron microscopy) and in situ zymography (EnzChek Protease Assay Kit). Bond strength data were submitted to ANOVA and Tukey tests (α=0.05). Results: Significant reduction in immediate bond strength (ca 65%) and increase in proteolytic activity was seen when the etched dentin was air dried without previous cross-linking biomodification. Conversely, bond strengths did not differ from those produced on wet dentin when collagen was cross-linked before air drying, irrespective of the solution applied. For both moist and air-dried etched dentin, collagen cross-linking resulted in mechanically stable bonds and reduced proteolytic activity after 12 months of storage. Conclusion: Bonds produced by the application of a two-step, etch-and-rinse adhesive to cross-linked, air-dried, etched dentin were mechanically stable and revealed reduced proteolytic activity after 1 year of aging.

scholarly journals Impact of fibrinogen carbamylation on fibrin clot formation and stability

2017 ◽  
Vol 117 (05) ◽  
pp. 899-910 ◽  
Author(s):  
Stéphane Jaisson ◽  
Philippe Gillery ◽  
Carsten Scavenius ◽  
Endy Spriet ◽  
Anne Nyhaug ◽  
...  
Keyword(s):  
Kidney Disease ◽  
Mechanical Stability ◽  
Inflammatory Diseases ◽  
Plasma Concentrations ◽  
Fibrin Clot ◽  
Clot Formation ◽  
Cross Linking ◽  
Post Translational Modification ◽  
The Impact

SummaryCarbamylation is a non-enzymatic post-translational modification induced upon exposure of free amino groups to urea-derived cyanate leading to irreversible changes of protein charge, structure and function. Levels of carbamylated proteins increase significantly in chronic kidney disease and carbamylated albumin is considered as an important biomarker indicating mortality risk. High plasma concentrations and long half-life make fibrinogen a prime target for carbamylation. As aggregation and cross-linking of fibrin monomers rely on lysine residues, it is likely that carbamylation impacts fibrinogen processing. In this study we investigated carbamylation levels of fibrinogen from kidney disease patients as well as the impact of carbamylation on fibrinogen cleavage by thrombin, fibrin polymerisation and cross-linking in vitro. In conjunction, all these factors determine clot structure and stability and thus control biochemical and mechanical properties. LC-MS/MS analyses revealed significantly higher homocitrulline levels in patient fibrinogen than in fibrinogen isolated from control plasma. In our in vitro studies we found that although carbamylation does not affect thrombin cleavage per se, it alters fibrin polymerisation kinetics and impairs cross-linking and clot degradation. In addition, carbamylated fibrin clots had reduced fiber size and porosity associated with decreased mechanical stability. Using mass spectroscopy, we discovered that N-terminally carbamylated fibrinopeptide A was generated in this process and acted as a strong neutrophil chemoattractant potentially mediating recruitment of inflammatory cells to sites of fibrin(ogen) turnover. Taken together, carbamylation of fibrinogen seems to play a role in aberrant fibrin clot formation and might be involved in haemostatic disorders associated with chronic inflammatory diseases.

scholarly journals Molecular processes of corneal collagen cross-linking in keratoconus therapy

2018 ◽  
Vol 4 (1) ◽  
pp. 489-492
Author(s):  
Steven Melcher ◽  
Eberhard Spörl ◽  
Edmund Koch ◽  
Gerald Steiner
Keyword(s):  
Mechanical Stability ◽  
Attenuated Total Reflection ◽  
Secondary Amines ◽  
Cross Linking ◽  
Therapeutic Effects ◽  
Corneal Tissue ◽  
In Situ Experiments ◽  
Cross Links ◽  
Collagen Cross Linking ◽  
Corneal Collagen

AbstractCorneal collagen cross-linking (CXL) with riboflavin and UVA light is a therapeutic procedure to restore the mechanical stability of corneal tissue. The treatment method applies to pathological tissue changes, such as keratoconus. It induces the photochemical formation of new collagen cross-links. Although therapeutic effects are indisputable, the exact molecular process of CXL and how cross-links are formed is still unclear. In this work, Fouriertransform infrared (FT-IR) spectroscopy is used to investigate the cross-linking process. For that purpose, in-situ experiments with porcine corneas are carried out using attenuated total reflection (ATR) spectroscopy. Furthermore, IR micro-spectroscopic imaging in transmission mode is used to investigate thin tissue sections of the cornea and initial approaches for the distinction of cross-linked and untreated tissue by IR microspectroscopic imaging were performed. Multivariate methods are applied to access changes that occur as a result of CXL. It is shown that spectral changes after cross-linking are caused predominantly by an increase of methyl- and methylene groups as well as primary and secondary amines. In addition, a decrease of carbonyl groups could be observed.

Photo-Cross-Linking Approach to Engineering Small Tyrosine-Containing Peptide Hydrogels with Enhanced Mechanical Stability

Langmuir ◽  
2013 ◽  
Vol 29 (43) ◽  
pp. 13299-13306 ◽  
Author(s):  
Yin Ding ◽  
Ying Li ◽  
Meng Qin ◽  
Yi Cao ◽  
Wei Wang
Keyword(s):  
Mechanical Stability ◽  
Cross Linking ◽  
Peptide Hydrogels

Evaluation of Wrinkle Recovery Angle & Color Fastness Properties of Ionic Crosslinked Hospital Green Vat Dyed Cotton Fabric

2012 ◽  
Vol 576 ◽  
pp. 300-304
Author(s):  
Umaima Saleem ◽  
Zeeshan Khatri ◽  
Muhammad Hanif Memon
Keyword(s):  
Mechanical Stability ◽  
Cross Linking ◽  
Ionic Character ◽  
Color Fastness ◽  
Fastness Properties ◽  
Ionic Content ◽  
Application Procedure ◽  
Cross Links ◽  
Recovery Angle ◽  
Green Vat

Cellulose cross linking is a very important textile process and has application in the crease resistant finished textile products. N-methylol cross linkers give fabrics desirable mechanical stability properties, but also reduces strength and release formaldehyde, a known human carcinogenic. Our work is based on reactions of particularly hospital green vat dyed cellulose with materials that creates an ionic character to the cellulose. These reactions produce ionic cellulose that can react with a poly ionic material of opposite charge to form cross links. The ionic content of the fabric and various features of the application procedure were varied to optimize the results.

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