Collagen Network Topology is Influenced by Collagen Concentration, But Not by Co-Gelation With Fibrin

2011 ◽  
Author(s):  
Victor K. Lai ◽  
Edward A. Sander ◽  
Spencer P. Lake ◽  
Robert T. Tranquillo ◽  
Victor H. Barocas
Keyword(s):  
Mechanical Properties ◽  
Healing Process ◽  
Biological Tissues ◽  
Wound Healing Process ◽  
Type I ◽  
Collagen Gels ◽  
Collagen Network ◽  
Modeling Framework ◽  
Collagen Concentration ◽  
Cardiovascular Tissue

Extracellular matrix (ECM) proteins (e.g. collagen, elastin) play an important role in biological tissues. In addition to conferring mechanical strength to a tissue, the ECM provides a biochemical environment essential for modulation of cellular responses such as growth and migration. Collagens are the dominant protein of the ECM, with collagen type I being most abundant. Our group and others have shown that the mechanical properties of a collagen I matrix change with collagen concentration, and when formed in the presence of a secondary fibril network such as fibrin [1]. We are interested in collagen-fibrin systems because our group uses fibrin as the starting scaffold material for cardiovascular tissue engineering, which produces interpenetrating collagen-fibrin matrices during the remodeling process as the fibrin network is degraded and replaced with cell-deposited collagen [2]. Fibrin and collagen networks are also present together around the thrombus during the wound healing process. Research has shown that ECM mechanical properties are correlated with their overall network structure characteristics such as fibril diameter [3]. Currently we have a modeling framework that generates an ECM microstructural network which can be used to predict the overall properties of a bioengineered tissue [4]. This framework allows exploration of the structure-function relation, but how the structure depends on composition remains poorly understood, especially in multi-component gels. Thus, the objective of this work was to quantify the collagen network architecture in pure collagen gels of different concentrations and in collagen-fibrin co-gels.

The Effect of Mechanical Constraints on Gelatin Samples under Pulsatile Flux

2012 ◽  
Vol 706-709 ◽  
pp. 449-454
Author(s):  
Eugenia Blangino ◽  
Martín A. Cagnoli ◽  
Ramiro M. Irastorza ◽  
Fernando Vericat
Keyword(s):  
Mechanical Properties ◽  
Tissue Engineering ◽  
Collagen Gel ◽  
Biological Tissues ◽  
Mechanical Stimuli ◽  
Collagen Gels ◽  
Collagen Network ◽  
Mechanical Constraints ◽  
Preparation Conditions ◽  
Biological Compatibility

It is of great interest in tissue engineering the role of collagen gel-based structures (scaffolds, grafts and-by cell seeded and maturation-tissue equivalents (TEs) for several purposes). It is expected the appropriate biological compatibility when the extracellular matrix (ECM) is collagen-based. Regarding the mechanical properties (MP), great efforts in tissue engineering are focused in tailoring TE properties by controlling ECM composition and organization. When cells are seeded, the collagen network is remodeled by cell-driven compaction and consolidation, produced mainly through the mechanical stimuli that can be directed selecting the geometry and the surfaces exposed to the cells. Collagen gels have different (chemical and mechanical) properties depending on their origin and preparation conditions. The MP of the collagen network are derived from the degree of cross-linking (CLD) which can be modified by different treatments. One of the techniques to evaluate MP in the network is by ultrasound (US). In this work we analyse the effect of several mechanical constraints (similar to that imposed to promote cell growth on certain sample surfaces, when seeded) on samples of gelatin with a specific geometry (thick walls cylinders) under loading conditions of pulsatile flow. We checked US parameters and estimates evolution of the network structure for different restrictions in the sample mobility. It was implemented by adapting devices specially built to measure elastic properties of biological tissues by US. The material (origin and purity) and the preparation conditions for the gelatin were selected in order to compare the results with those of literature.

scholarly journals Design and construction of a novel measurement device for mechanical characterization of hydrogels: A case study

PLoS ONE ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. e0247727
Author(s):  
Shayan Shahab ◽  
Mehran Kasra ◽  
Alireza Dolatshahi-Pirouz
Keyword(s):  
Mechanical Properties ◽  
Shear Modulus ◽  
Magnetic Beads ◽  
Mechanical Characterization ◽  
Collagen Gel ◽  
Biological Tissues ◽  
Elastic Behavior ◽  
Collagen Gels ◽  
Collagen Concentration

Natural biopolymer-based hydrogels especially agarose and collagen gels, considering their biocompatibility with cells and their capacity to mimic biological tissues, have widely been used for in-vitro experiments and tissue engineering applications in recent years; nevertheless their mechanical properties are not always optimal for these purposes. Regarding the importance of the mechanical properties of hydrogels, many mechanical characterization studies have been carried out for such biopolymers. In this work, we have focused on understanding the mechanical role of agarose and collagen concentration on the hydrogel strength and elastic behavior. In this direction, Amirkabir Magnetic Bead Rheometry (AMBR) characterization device equipped with an optimized electromagnet, was designed and constructed for the measurement of hydrogel mechanical properties. The operation of AMBR set-up is based on applying a magnetic field to actuate magnetic beads in contact with the gel surface in order to actuate the gel itself. In simple terms the magnetic beads leads give rise to mechanical shear stress on the gel surface when under magnetic influence and together with the associated bead-gel displacement it is possible to calculate the hydrogel shear modulus. Agarose and Collagen gels with respectively 0.2–0.6 wt % and 0.2–0.5 wt % percent concentrations were prepared for mechanical characterization in terms of their shear modulus. The shear modulus values for the different percent concentrations of the agarose gel were obtained in the range 250–650 Pa, indicating the shear modulus increases by increasing in the agar gel concentration. In addition to this, the values of shear modulus for the collagen gel increase as function of concentration in the range 240–520 Pa in accordance with an approximately linear relationship between collagen concentration and gel strength.

Comparative Analysis of the Proteomic Profile of Cattle Hides that Produce Loose and Tight Leather using In-Gel Tryptic Digestion followed by LC-MS/MS

2020 ◽  
Vol 115 (11) ◽  
pp. 399-408
Author(s):  
Catherine Maidment ◽  
Meekyung Ahn ◽  
Rafea Naffa ◽  
Trevor Loo ◽  
Gillian Norris
Keyword(s):  
Type I Collagen ◽  
Raw Material ◽  
Type I ◽  
Collagen Structure ◽  
Proteomic Profile ◽  
Collagen Network ◽  
Collagen Concentration ◽  
Different Types ◽  
Molecular Components ◽  
First Time

Looseness is a defect found in leather that reduces its quality by causing a wrinkly appearance in the finished product, resulting in a reduction in its value. Earlier studies on loose leather using microscopy and Raman spectroscopy reported a change in the collagen structure of loose leather. In this study, proteomics was used to investigate the possible molecular causes of looseness in the raw material, the first time such a study has been carried out. Proteins extracted from two regions of raw hide using two different methods were analysed; those taken from the distal axilla, an area prone to looseness, and those taken from the backbone which is less prone to looseness. Analyses using 1DE-LC-MS/MS showed that although the overall collagen concentration was similar in both areas of the hide, the distribution of the different types of collagen differed.  Specifically, concentrations of type I collagen, and the collagen-associated proteoglycan decorin were lower in samples taken from the distal axilla, symptomatic of a collagen network with excess space seen for these samples using confocal microscopy. This study suggests a possible link between the molecular components of raw cattle hide and looseness and more importantly between the molecular components of skin and skin defects. There is therefore potential to develop biomarkers for looseness which will enable early preventative action.

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.

scholarly journals Specific PKC βII inhibitor: one stone two birds in the treatment of diabetic foot ulcers

2018 ◽  
Vol 38 (5) ◽  
Author(s):  
Sushant Kumar Das ◽  
Yi Feng Yuan ◽  
Mao Quan Li
Keyword(s):  
Wound Healing ◽  
Protein Kinase ◽  
Peripheral Blood ◽  
Wound Closure ◽  
Type I Diabetes ◽  
Healing Process ◽  
Wound Healing Process ◽  
Peripheral Blood Flow ◽  
Type I ◽  
Diabetic Mice

To explore whether or not inhibition of protein kinase C βII (PKC βII) stimulates angiogenesis as well as prevents excessive NETosis in diabetics thus accelerating wound healing. Streptozotocin (STZ, 60 mg/kg/day for 5 days, i.p.) was injected to induce type I diabetes in male ICR mice. Mice were treated with ruboxistaurin (30 mg/kg/day, orally) for 14 consecutive days. Wound closure was evaluated by wound area and number of CD31-stained capillaries. Peripheral blood flow cytometry was done to evaluate number of circulating endothelial progenitor cells (EPCs). NETosis assay and wound tissue immunofluorescence imaging were done to evaluate the percentage of neutrophils undergoing NETosis. Furthermore, the expression of PKC βII, protein kinase B (Akt), endothelial nitric oxide synthase (eNOS), vascular endothelial growth factor (VEGF), and histone citrullation (H3Cit) were determined in the wound by Western blot analysis. Ruboxistaurin accelerated wound closure and stimulated angiogenesis in diabetic mice. The number of circulating EPCs was increased significantly in ruboxistaurin-treated diabetic mice. Moreover, ruboxistaurin treatment significantly decreases the percentages of H3Cit+ cells in both peripheral blood and wound areas. This prevented excess activated neutrophils forming an extracellular trap (NETs) formation. The expressions of phospho-Akt (p-Akt), phospho-eNOS (p-eNOS), and VEGF increased significantly in diabetic mice on ruboxistaurin treatment. The expressions of PKC βII and H3Cit+, on the other hand, decreased with ruboxistaurin treatment. The results of the present study suggest that ruboxistaurin by inhibiting PKC βII activation, reverses EPCs dysfunction as well as prevents exaggerated NETs formation in a diabetic mouse model; thereby accelerating the wound healing process.

Mechanical Properties of Collagen-Fibrin Co-Gels

2009 ◽  
Author(s):  
Victor K. Lai ◽  
Edward A. Sander ◽  
Robert T. Tranquillo ◽  
Victor H. Barocas
Keyword(s):  
Mechanical Properties ◽  
Healing Process ◽  
Mechanical Tests ◽  
Functional Requirements ◽  
Interpenetrating Networks ◽  
Modeling Framework ◽  
Fibrin Gels ◽  
Multi Scale ◽  
Engineered Tissues ◽  
Anisotropic Mechanical Properties

Achieving desired mechanical properties is critical to meeting the functional requirements of engineered tissues. Mechanical function is inextricably linked to tissue structure. For example, replacement of fibrin with collagen during the healing process results in compositional heterogeneity which governs mechanical strength and function. Artificial tissues engineered using biopolymers such as fibrin and collagen can undergo a remodeling process that produces a compositionally and structurally complex tissue equivalent (TE) with anisotropic mechanical properties. TE functionality is assessed in part through mechanical testing, but the TE response is dependent on multi-scale interactions, which are dependent on a heterogeneously distributed microstructure, and are therefore difficult to interpret. In order to unravel the coupling between TE microstructure and macroscopic mechanical behavior, we have developed a multi-scale modeling framework for incorporating single component microstructural networks [1]. To expand our modeling framework, it is necessary to incorporate interpenetrating fibrin and collagen networks. This issue is particularly critical towards understanding the remodeling process that occurs in fibrin gels, which gradually replace fibrin with collagen networks. In this work, we have begun to investigate interpenetrating fibrin-collagen co-gels by varying the co-gel composition and subjecting the gels to uniaxial mechanical tests [2]. This study lays the experimental foundation for determining how to construct interpenetrating networks for our multiscale modeling framework, which will ultimately allows us to better assess and predict TE mechanics and produce better engineered tissues.

scholarly journals Gelatin-Based Hybrid Scaffolds: Promising Wound Dressings

Polymers ◽  
2021 ◽  
Vol 13 (17) ◽  
pp. 2959 ◽  
Author(s):  
Sindi P. Ndlovu ◽  
Kwanele Ngece ◽  
Sibusiso Alven ◽  
Blessing A. Aderibigbe
Keyword(s):  
Mechanical Properties ◽  
Antimicrobial Activity ◽  
Wound Healing ◽  
Antimicrobial Agents ◽  
Healing Process ◽  
Wound Dressings ◽  
Wound Healing Process ◽  
Delayed Wound Healing

Wound care is a major biomedical field that is challenging due to the delayed wound healing process. Some factors are responsible for delayed wound healing such as malnutrition, poor oxygen flow, smoking, diseases (such as diabetes and cancer), microbial infections, etc. The currently used wound dressings suffer from various limitations, including poor antimicrobial activity, etc. Wound dressings that are formulated from biopolymers (e.g., cellulose, chitin, gelatin, chitosan, etc.) demonstrate interesting properties, such as good biocompatibility, non-toxicity, biodegradability, and attractive antimicrobial activity. Although biopolymer-based wound dressings display the aforementioned excellent features, they possess poor mechanical properties. Gelatin, a biopolymer has excellent biocompatibility, hemostatic property, reduced cytotoxicity, low antigenicity, and promotes cellular attachment and growth. However, it suffers from poor mechanical properties and antimicrobial activity. It is crosslinked with other polymers to enhance its mechanical properties. Furthermore, the incorporation of antimicrobial agents into gelatin-based wound dressings enhance their antimicrobial activity in vitro and in vivo. This review is focused on the development of hybrid wound dressings from a combination of gelatin and other polymers with good biological, mechanical, and physicochemical features which are appropriate for ideal wound dressings. Gelatin-based wound dressings are promising scaffolds for the treatment of infected, exuding, and bleeding wounds. This review article reports gelatin-based wound dressings which were developed between 2016 and 2021.

scholarly journals The Effectiveness of Depigmentation, Interleukin-1B, and Transforming Growth Factor-B Antibodies in Activating and Increasing Collagenase in Keloid as Adjuvant Therapy After Scar Excision

2021 ◽  
Vol 2 (1) ◽  
pp. 16-22
Author(s):  
Savira Butsainah Dienanta ◽  
Ayik Rochyatul Jannah ◽  
Faiza Rahma Ebnudesita ◽  
Reny I'tishom
Keyword(s):  
Growth Factor ◽  
Adjuvant Therapy ◽  
Collagen Synthesis ◽  
Type I Collagen ◽  
Transforming Growth Factor ◽  
Target Location ◽  
Drug Carrier ◽  
Healing Process ◽  
Wound Healing Process ◽  
Type I

Background: Keloid is an abnormal scar in previously traumatic skin after going through the wound healing process. One hundred million cases have been found in developing countries with the main complaint of scar appearances. To overcome this problem, 24 literatures from various journals and textbooks are reviewed. Reviews: Keloid formation is based on high melanin amount which inhibits the collagenase enzyme. Moreover, the high melanin amount would block interleukin (IL)-1B work resulting in collagen synthesis and collagenase reduction. Depigmentation effort with 4% hydroquinone is implemented to reduce the amount of melanin presented in the skin. With melanin reduction, IL-1B can work optimally by inhibiting fibroblast growth in keloid tissue without affecting on normal skin. It also induces Matrix Metalloproteinase (MMP)-1 which is an interstitial collagenase. IL-1B has an opposing effect compared to Transforming Growth Factor (TGF)-B, thus TGF-B antibody is needed to potentiate IL-1B therapeutic effect. TGF-B antibody can neutralize TGF-B ligand and avB6 integrin resulting in blocking of COL1A1 gene expression which is responsible for MMP-1 production and type-I collagen synthesis. These three components are combined in cream with liposome as a drug carrier. This combination is applicated for adjuvant therapy after scar excision. Liposomes are chosen because of their high biocompatibility, low toxicity, and low biodegradability. Liposomes also can release slowly in the extravascular area such as skin. This advantage may carry drug components effectively to the target location. Summary: The combination of depigmentation, IL-1B, and TGF-B antibodies has a potency to be developed as a future adjuvant therapy of keloid.

scholarly journals pH Modification of High-Concentrated Collagen Bioinks as a Factor Affecting Cell Viability, Mechanical Properties, and Printability

Gels ◽  
2021 ◽  
Vol 7 (4) ◽  
pp. 252
Author(s):  
Jana Stepanovska ◽  
Martin Otahal ◽  
Karel Hanzalek ◽  
Monika Supova ◽  
Roman Matejka
Keyword(s):  
Mechanical Properties ◽  
Cell Proliferation ◽  
Cell Viability ◽  
Limiting Factor ◽  
Mechanical Resistance ◽  
3D Bioprinting ◽  
Collagen Gels ◽  
High Concentration ◽  
Collagen Concentration ◽  
Static Conditions

The 3D bioprinting of cell-incorporated gels is a promising direction in tissue engineering applications. Collagen-based hydrogels, due to their similarity to extracellular matrix tissue, can be a good candidate for bioink and 3D bioprinting applications. However, low hydrogel concentrations of hydrogel (<10 mg/mL) provide insufficient structural support and, in highly concentrated gels, cell proliferation is reduced. In this study, we showed that it is possible to print highly concentrated collagen hydrogels with incorporated cells, where the viability of the cells in the gel remains very good. This can be achieved simply by optimizing the properties of the bioink, particularly the gel composition and pH modification, as well as by optimizing the printing parameters. The bioink composed of porcine collagen hydrogel with a collagen concentration of 20 mg/mL was tested, while the final bioink collagen concentration was 10 mg/mL. This bioink was modified with 0, 5, 9, 13, 17 and 20 μL/mL of 1M NaOH solution, which affected the resulting pH and gelling time. Cylindrical samples based on the given bioink, with the incorporation of porcine adipose-derived stromal cells, were printed with a custom 3D bioprinter. These constructs were cultivated in static conditions for 6 h, and 3 and 5 days. Cell viability and morphology were evaluated. Mechanical properties were evaluated by means of a compression test. Our results showed that optimal composition and the addition of 13 μL NaOH per mL of bioink adjusted the pH of the bioink enough to allow cells to grow and divide. This modification also contributed to a higher elastic modulus, making it possible to print structures up to several millimeters with sufficient mechanical resistance. We optimized the bioprinter parameters for printing low-viscosity bioinks. With this experiment, we showed that a high concentration of collagen gels may not be a limiting factor for cell proliferation.

Collagen membranes for skin wound repair: A systematic review

2020 ◽  
pp. 088532822098027
Author(s):  
Tiago Akira Tashiro Araujo ◽  
Matheus Cruz Almeida ◽  
Ingrid Avanzi ◽  
Julia Parisi ◽  
Abdias Fernando Simon Sales ◽  
...  
Keyword(s):  
Systematic Review ◽  
Wound Healing ◽  
Healing Process ◽  
Biological Tissues ◽  
Skin Wound ◽  
Wound Healing Process ◽  
Skin Wound Healing ◽  
Efficient Treatment ◽  
Positive Effects ◽  
Collagen Membranes

Membranes or skin dressing are common treatments for skin wound injuries, collagen being one the most effective materials for their manufacturing. Many different sources of collagen with diverse methods of extraction and processing have been used, with evidence of positive effects on the stimulation of skin wound healing. In spite of these factors, there is still limited understanding of the interaction between collagen membranes and biological tissues, especially due to the series of different types of collagen origin. In this context, this study aimed to conduct a systematic review of the available literature examining the effect of various collagen membranes for accelerating skin wound healing in experimental animal models and clinical trials. The present review was performed from March to May of 2020 searching in two databases (PubMed and Scopus). The following Medical Subject Headings (MeSH) descriptors were used: “collagen”, “dressing”, “membranes”, “skin” and “wound”. After the eligibility assessment, 16 studies were included and analyzed. The studies demonstrated that collagen was obtained predominantly from bovine and porcine sources, by acetic acid and/or enzyme dissolution. Additionally, most of the studies demonstrated that the membranes were processed mainly by freeze-drying or lyophilization methods. All the in vivo and clinical trial studies evidenced positive outcomes in the wound healing process, thus confirming that collagen membranes are one of the most efficient treatment for skin wounds, highlighting the enormous potential of this biomaterial to be used for skin tissue engineering purposes.

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