scholarly journals Multi-scale mechanical characterization of highly swollen photo-activated collagen hydrogels

2015 ◽  
Vol 12 (102) ◽  
pp. 20141079 ◽  
Author(s):  
Giuseppe Tronci ◽  
Colin A. Grant ◽  
Neil H. Thomson ◽  
Stephen J. Russell ◽  
David J. Wood
Keyword(s):  
Mechanical Properties ◽  
Type I Collagen ◽  
Wound Care ◽  
Wound Dressings ◽  
Type I ◽  
Structure Property ◽  
Multi Scale ◽  
Macro Scale ◽  
Collagen Hydrogels ◽  
Tunable Mechanical Properties

Biological hydrogels have been increasingly sought after as wound dressings or scaffolds for regenerative medicine, owing to their inherent biofunctionality in biological environments. Especially in moist wound healing, the ideal material should absorb large amounts of wound exudate while remaining mechanically competent in situ . Despite their large hydration, however, current biological hydrogels still leave much to be desired in terms of mechanical properties in physiological conditions. To address this challenge, a multi-scale approach is presented for the synthetic design of cyto-compatible collagen hydrogels with tunable mechanical properties (from the nano- up to the macro-scale), uniquely high swelling ratios and retained (more than 70%) triple helical features. Type I collagen was covalently functionalized with three different monomers, i.e. 4-vinylbenzyl chloride, glycidyl methacrylate and methacrylic anhydride, respectively. Backbone rigidity, hydrogen-bonding capability and degree of functionalization ( F : 16 ± 12–91 ± 7 mol%) of introduced moieties governed the structure–property relationships in resulting collagen networks, so that the swelling ratio ( SR : 707 ± 51–1996 ± 182 wt%), bulk compressive modulus ( E c : 30 ± 7–168 ± 40 kPa) and atomic force microscopy elastic modulus ( E AFM : 16 ± 2–387 ± 66 kPa) were readily adjusted. Because of their remarkably high swelling and mechanical properties, these tunable collagen hydrogels may be further exploited for the design of advanced dressings for chronic wound care.

scholarly journals Comprehensive Assessment of Nile Tilapia Skin (Oreochromis niloticus) Collagen Hydrogels for Wound Dressings

Marine Drugs ◽  
2020 ◽  
Vol 18 (4) ◽  
pp. 178 ◽  
Author(s):  
Baosheng Ge ◽  
Haonan Wang ◽  
Jie Li ◽  
Hengheng Liu ◽  
Yonghao Yin ◽  
...  
Keyword(s):  
Wound Dressing ◽  
Type I Collagen ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Wound Dressings ◽  
Type I ◽  
Rheological Characterization ◽  
Scanning Calorimetry ◽  
Soluble Collagen ◽  
Collagen Hydrogels

Collagen plays an important role in the formation of extracellular matrix (ECM) and development/migration of cells and tissues. Here we report the preparation of collagen and collagen hydrogel from the skin of tilapia and an evaluation of their potential as a wound dressing for the treatment of refractory wounds. The acid-soluble collagen (ASC) and pepsin-soluble collagen (PSC) were extracted and characterized using sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE), differential scanning calorimetry (DSC), circular dichroism (CD) and Fourier transform infrared spectroscopy (FTIR) analysis. Both ASC and PSC belong to type I collagen and have a complete triple helix structure, but PSC shows lower molecular weight and thermal stability, and has the inherent low antigenicity. Therefore, PSC was selected to prepare biomedical hydrogels using its self-aggregating properties. Rheological characterization showed that the mechanical strength of the hydrogels increased as the PSC content increased. Scanning electron microscope (SEM) analysis indicated that hydrogels could form a regular network structure at a suitable PSC content. Cytotoxicity experiments confirmed that hydrogels with different PSC content showed no significant toxicity to fibroblasts. Skin repair experiments and pathological analysis showed that the collagen hydrogels wound dressing could significantly accelerate the healing of deep second-degree burn wounds and the generation of new skin appendages, which can be used for treatment of various refractory wounds.

scholarly journals Structure-property-function relationships in triple-helical collagen hydrogels

2012 ◽  
Vol 1498 ◽  
pp. 145-150 ◽  
Author(s):  
Giuseppe Tronci ◽  
Amanda Doyle ◽  
Stephen J. Russell ◽  
David J. Wood
Keyword(s):  
Triple Helix ◽  
Type I Collagen ◽  
Molecular Organization ◽  
Type I ◽  
Tissue Formation ◽  
Structure Property ◽  
Mineralized Tissue ◽  
Mineral Deposition ◽  
Collagen Hydrogels ◽  
Macroscopic Properties

ABSTRACTIn order to establish defined biomimetic systems, type I collagen was functionalised with 1,3-Phenylenediacetic acid (Ph) as aromatic, bifunctional segment. Following investigation on molecular organization and macroscopic properties, material functionalities, i.e. degradability and bioactivity, were addressed, aiming at elucidating the potential of this collagen system as mineralization template. Functionalised collagen hydrogels demonstrated a preserved triple helix conformation. Decreased swelling ratio and increased thermo-mechanical properties were observed in comparison to state-of-the-art carbodiimide (EDC)-crosslinked collagen controls. Ph-crosslinked samples displayed no optical damage and only a slight mass decrease (∼ 4 wt.-%) following 1-week incubation in simulated body fluid (SBF), while nearly 50 wt.-% degradation was observed in EDC-crosslinked collagen. SEM/EDS revealed amorphous mineral deposition, whereby increased calcium phosphate ratio was suggested in hydrogels with increased Ph content. This investigation provides valuable insights for the synthesis of triple helical collagen materials with enhanced macroscopic properties and controlled degradation. In light of these features, this system will be applied for the design of tissue-like scaffolds for mineralized tissue formation.

scholarly journals The effect of collagen hydrogels on chondrocyte behaviors through restricting the contraction of cell/hydrogel constructs

2021 ◽  
Vol 8 (4) ◽  
Author(s):  
Longpeng Dong ◽  
Qingli Liu ◽  
Yongli Gao ◽  
Hengxing Jia ◽  
Wenling Dai ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Type I Collagen ◽  
Cell Counting ◽  
Type I ◽  
Dna Assays ◽  
Collagen Hydrogels ◽  
Degradation Properties ◽  
Histological Staining

Abstract Collagen is a promising material for tissue engineering, but the poor mechanical properties of collagen hydrogels, which tend to cause contraction under the action of cellular activity, make its application challengeable. In this study, the amino group of type I collagen (Col I) was modified with methacrylic anhydride (MA) and the photo-crosslinkable methacrylate anhydride modified type I collagen (CM) with three different degrees of substitution (DS) was prepared. The physical properties of CM and Col I hydrogels were tested, including micromorphology, mechanical properties and degradation properties. The results showed that the storage modulus and degradation rate of hydrogels could be adjusted by changing the DS of CM. In vitro, chondrocytes were seeded into these four groups of hydrogels and subjected to fluorescein diacetate/propidium iodide (FDA/PI) staining, cell counting kit-8 (CCK-8) test, histological staining and cartilage-related gene expression analysis. In vivo, these hydrogels encapsulating chondrocytes were implanted subcutaneously into nude mice, then histological staining and sulfated glycosaminoglycan (sGAG)/DNA assays were performed. The results demonstrated that contraction of hydrogels affected behaviors of chondrocytes, and CM hydrogels with suitable DS could resist contraction of hydrogels and promote the secretion of cartilage-specific matrix in vitro and in vivo.

scholarly journals Influence of 4-vinylbenzylation on the rheological and swelling properties of photo-activated collagen hydrogels

MRS Advances ◽  
2015 ◽  
Vol 1 (8) ◽  
pp. 533-538 ◽  
Author(s):  
Giuseppe Tronci ◽  
Colin A. Grant ◽  
Neil H. Thomson ◽  
Stephen J. Russell ◽  
David J. Wood
Keyword(s):  
Mechanical Properties ◽  
Rheological Properties ◽  
Type I Collagen ◽  
Adhesion Force ◽  
Aqueous Environment ◽  
Type I ◽  
Swelling Properties ◽  
Force Microscopy ◽  
Collagen Hydrogels ◽  
And Control

ABSTRACTCovalent functionalisation of collagen has been shown to be a promising strategy to adjust the mechanical properties of highly swollen collagen hydrogels. At the same time, secondary interactions between for example, amino acidic terminations or introduced functional groups also play an important role and are often challenging to predict and control. To explore this challenge, 4-vinylbenzyl chloride (4VBC) and methacrylic anhydride (MA) were reacted with type I collagen, and the swelling and rheological properties of resulting photo-activated hydrogel systems investigated. 4VBC-based hydrogels showed significantly increased swelling ratio, in light of the lower degree of collagen functionalisation, with respect to methacrylated collagen networks, whilst rheological storage moduli were found to be comparable between the two systems. To explore the role of benzyl groups in the mechanical properties of the 4VBC-based collagen system, model chemical force microscopy (CFM) was carried out in aqueous environment with an aromatised probe against an aromatised gold-coated glass slide. A marked increase in adhesion force (F: 0.11±0.01 nN) was measured between aromatised samples, compared to the adhesion force observed between the non-modified probe and a glass substrate (F: 2.64±1.82 nN). These results suggest the formation of additional and reversible π-π stacking interactions in aromatic 4VBC-based networks and explain the remarkable rheological properties of this system in comparison to MA-based hydrogels.

Intrinsic mechanical properties of the extracellular matrix affect the behavior of pre-osteoblastic MC3T3-E1 cells

2006 ◽  
Vol 290 (6) ◽  
pp. C1640-C1650 ◽  
Author(s):  
Chirag B. Khatiwala ◽  
Shelly R. Peyton ◽  
Andrew J. Putnam
Keyword(s):  
Mechanical Properties ◽  
Type I Collagen ◽  
Focal Adhesions ◽  
Microscopic Analysis ◽  
Maximal Activity ◽  
Type I ◽  
Cell Functions ◽  
Collagen Density ◽  
Cells Cultured ◽  
In Cells

Mechanical cues present in the ECM have been hypothesized to provide instructive signals that dictate cell behavior. We probed this hypothesis in osteoblastic cells by culturing MC3T3-E1 cells on the surface of type I collagen-modified hydrogels with tunable mechanical properties and assessed their proliferation, migration, and differentiation. On gels functionalized with a low type I collagen density, MC3T3-E1 cells cultured on polystyrene proliferated twice as fast as those cultured on the softest substrate. Quantitative time-lapse video microscopic analysis revealed random motility speeds were significantly retarded on the softest substrate (0.25 ± 0.01 μm/min), in contrast to maximum speeds on polystyrene substrates (0.42 ± 0.04 μm/min). On gels functionalized with a high type I collagen density, migration speed exhibited a biphasic dependence on ECM compliance, with maximum speeds (0.34 ± 0.02 μm/min) observed on gels of intermediate stiffness, whereas minimum speeds (0.24 ± 0.03 μm/min) occurred on both the softest and most rigid (i.e., polystyrene) substrates. Immature focal contacts and a poorly organized actin cytoskeleton were observed in cells cultured on the softest substrates, whereas those on more rigid substrates assembled mature focal adhesions and robust actin stress fibers. In parallel, focal adhesion kinase (FAK) activity (assessed by detecting pY397-FAK) was influenced by compliance, with maximal activity occurring in cells cultured on polystyrene. Finally, mineral deposition by the MC3T3-E1 cells was also affected by ECM compliance, leading to the conclusion that altering ECM mechanical properties may influence a variety of MC3T3-E1 cell functions, and perhaps ultimately, their differentiated phenotype.

Assembly of type I collagen: fusion of fibril subunits and the influence of fibril diameter on mechanical properties

2000 ◽  
Vol 19 (5) ◽  
pp. 409-420 ◽  
Author(s):  
David L. Christiansen ◽  
Eric K. Huang ◽  
Frederick H. Silver
Keyword(s):  
Mechanical Properties ◽  
Type I Collagen ◽  
Type I ◽  
Fibril Diameter

scholarly journals Mechanical Properties of Native and Cross-linked Type I Collagen Fibrils

2008 ◽  
Vol 94 (6) ◽  
pp. 2204-2211 ◽  
Author(s):  
Lanti Yang ◽  
Kees O. van der Werf ◽  
Carel F.C. Fitié ◽  
Martin L. Bennink ◽  
Pieter J. Dijkstra ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Type I Collagen ◽  
Collagen Fibrils ◽  
Type I

scholarly journals Sintesis Hidrogel Pektin – Gelatin dengan Penambahan Ekstrak Kulit Buah Naga Sebagai Kandidat Pembalut Luka Bakar

2020 ◽  
Vol 4 (1) ◽  
pp. 53
Author(s):  
Fadhil Muhammad Tarmidzi ◽  
Inggit Kresna Maharsih ◽  
Tina Raihatul Jannah ◽  
Cici Sari Wahyuni
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Citric Acid ◽  
Wound Dressing ◽  
Wound Care ◽  
Crosslinking Agent ◽  
Wound Dressings ◽  
Esterification Reaction ◽  
Natural Polymers ◽  
Fruit Peel

Teknik pembalutan luka saat ini menerapkan metode perawatan luka modern dengan cara mempertahankan isolasi lingkungan luka dalam keadaan tertutup dan lembab. Ada beberapa jenis pembalut luka yang telah dikembangkan, salah satunya hidrogel. Hidrogel merupakan pembalut luka berbentuk lembaran yang memiliki kemampuan menyerap cairan luka dan memiliki stabilitas yang baik pada pH asam sehingga dapat digunakan untuk pengobatan luka bakar. Dalam penelitian ini, hidrogel dibuat menggunakan polimer alami seperti pektin dan gelatin. Kedua bahan tersebut dikombinasikan menggunakan metode ikatan silang dengan penambahan asam sitrat sebagai agen pengikat silang. Penambahan asam sitrat memberikan pengaruh terhadap karakteristik material hidrogel yang dihasilkan, sehingga diperlukan jumlah yang tepat agar didapatkan hidrogel dengan properti material yang baik. Hidrogel juga ditambahkan zat aktif berupa flavonoid pada ekstrak kulit buah naga agar dapat digunakan sebagai pembalut luka untuk menyembuhkan luka bakar. Dari hasil penelitian, hidrogel dengan konsentrasi asam sitrat 4% (Hidrogel CA 4%) menghasilkan nilai swelling, tensile strength, dan elongation tertinggi sebesar 890%, 0,05 Mpa, dan 200%. Hasil properti mekanik dari Hidrogel CA 4% ini dibuktikan dengan uji FTIR yang telah dilakukan, yaitu munculnya gugus karbonil C=O sebagai hasil reaksi esterifikasi yang terjadi antara polimer dengan asam sitrat di daerah serapan 1733,9 cm-1.Wound dressing technique currently applies modern wound care methods by maintaining the environmental isolation of the wound in a closed and moist state. There are several types of wound dressing that have been developed, one of them is hydrogel. Hydrogel is sheet-shaped wound dressings which have the ability to absorb exudate and have good stability acidic pH that can be used for the treatment of burns. In this study, hydrogel were made using natural polymers such as pectin and gelatin. The two polymers were combined using crosslinking method with the addition of citric acid as a crosslinking agent. The addition of citric acid has affect on the characteristics of the hydrogel material produced, therefore the right amount is needed to obtain a hydrogel with good mechanical properties. Hydrogel also added by an active substance in the form of flavonoids from dragon fruit peel extract that can be used as a wound dressing to cure burns. This study resulting hydrogel with a concentration of 4% citric acid (Hydrogel CA 4%) produced highest value of swelling, tensile strength, and elongation are 890%, 0.05 Mpa, and 200%, repectively. The mechanical properties of Hydrogel CA 4% was proved by FTIR test that had been carried out, namely the presence of C=O carbonyl group as a result of the esterification reaction that occurred between the polymers and citric acid in the absorption area of 1733.9 cm-1.

scholarly journals Regenerative Rehabilitation in Injuries of Tendons

2021 ◽  
Vol 3 (2) ◽  
pp. 192-206
Author(s):  
Sergey G. Sсherbak ◽  
Stanislav V. Makarenko ◽  
Olga V. Shneider ◽  
Tatyana A. Kamilova ◽  
Alexander S. Golota
Keyword(s):  
Mechanical Properties ◽  
Type I Collagen ◽  
Transforming Growth Factor ◽  
Healing Process ◽  
Tendon Healing ◽  
Tendon Injuries ◽  
Type I ◽  
Differentiation Markers ◽  
Postoperative Rehabilitation ◽  
Potent Inducer

The mechanical properties of tendons are thought to be affected by different loading levels. Changes in the mechanical properties of tendons, such as stiffness, have been reported to influence the risk of tendon injuries chiefly in athletes and the elderly, thereby affecting motor function execution. Unloading resulted in reduced tendons stiffness, and resistance exercise exercise counteracts this. Transforming growth factor-1 is a potent inducer of type I collagen and mechanosensitive genes encoding tenogenic differentiation markers expression which play critical roles in tendon tissue formation, tendon healing and their adaptation during exercise. In recent years, our understanding of the molecular biology of tendons growth and repair has expanded. It is probable that the next advance in the treatment of tendon injuries will result from the application of this basic science knowledge and the clinical solution will encompass not only the the best postoperative rehabilitation protocols, but also the optimal biological modulation of the healing process.

Comparing Micro- and Macro-Level Rheological Properties of Polymeric and Reclaimed Asphalt Pavement-Modified Asphalt Binders

2021 ◽  
pp. 036119812110288
Author(s):  
Tandra Bagchi ◽  
Zahid Hossain ◽  
Mohammed Ziaur Rahaman ◽  
Gaylon Baumgardner
Keyword(s):  
Mechanical Properties ◽  
Scale Effects ◽  
Asphalt Pavement ◽  
Linear Trend ◽  
Asphalt Binders ◽  
Reclaimed Asphalt Pavement ◽  
Reclaimed Asphalt ◽  
Multi Scale ◽  
Macro Scale ◽  
Scale Properties

Multi-scale evaluation of the rheological and mechanical properties of asphalt binder has substantial importance in understanding the binder’s micro- and macro-scale properties. This study compares the macro- and micro-scale mechanistic properties of asphalt binders. Test samples used in this study include performance grade binders (PG 64-22) from two different sources along with their modified counterparts. The modifiers include polyphosphoric acid (PPA), styrene-butadiene-styrene (SBS), a combination of SBS and PPA, and reclaimed asphalt pavement. To achieve the goal of this study, atomic force microscope technology was utilized to estimate the asphalt binder’s micro-mechanical properties (e.g., Derjaguin, Muller, Toropov modulus and deformation). On the other hand, data on the macro-scale properties—such as rutting factor (G*/sinδ), consistency and penetration—of the selected binders were analyzed and compared with the aforementioned micro-level properties. The comparative analyses indicated that the micro-mechanical properties of asphalt binders followed a linear trend with the macro-scale properties. The findings of this study are expected to help researchers and pavement professionals in modeling asphalt materials when multi-scale effects are deemed to be necessary.

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