scholarly journals Mathematical Modeling of Uniaxial Mechanical Properties of Collagen Gel Scaffolds for Vascular Tissue Engineering

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Ramiro M. Irastorza ◽  
Bernard Drouin ◽  
Eugenia Blangino ◽  
Diego Mantovani
Keyword(s):  
Mechanical Properties ◽  
Tissue Engineering ◽  
Vascular Tissue ◽  
Nonlinear Models ◽  
Small Diameter ◽  
Collagen Gel ◽  
Vascular Tissue Engineering ◽  
Suitable Model ◽  
Collagen Gels ◽  
Hammerstein Models

Small diameter tissue-engineered arteries improve their mechanical and functional properties when they are mechanically stimulated. Applying a suitable stress and/or strain with or without a cycle to the scaffolds and cells during the culturing process resides in our ability to generate a suitable mechanical model. Collagen gel is one of the most used scaffolds in vascular tissue engineering, mainly because it is the principal constituent of the extracellular matrix for vascular cells in human. The mechanical modeling of such a material is not a trivial task, mainly for its viscoelastic nature. Computational and experimental methods for developing a suitable model for collagen gels are of primary importance for the field. In this research, we focused on mechanical properties of collagen gels under unconfined compression. First, mechanical viscoelastic models are discussed and framed in the control system theory. Second, models are fitted using system identification. Several models are evaluated and two nonlinear models are proposed: Mooney-Rivlin inspired and Hammerstein models. The results suggest that Mooney-Rivlin and Hammerstein models succeed in describing the mechanical behavior of collagen gels for cyclic tests on scaffolds (with best fitting parameters 58.3% and 75.8%, resp.). When Akaike criterion is used, the best is the Mooney-Rivlin inspired model.

scholarly journals Effects of a Pseudophysiological Environment on the Elastic and Viscoelastic Properties of Collagen Gels

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Sébastien Meghezi ◽  
Frédéric Couet ◽  
Pascale Chevallier ◽  
Diego Mantovani
Keyword(s):  
Mechanical Properties ◽  
Tissue Engineering ◽  
Viscoelastic Properties ◽  
Saline Solution ◽  
Vascular Tissue ◽  
Small Diameter ◽  
Tensile Tests ◽  
Biological Properties ◽  
Vascular Tissue Engineering ◽  
Collagen Gels

Vascular tissue engineering focuses on the replacement of diseased small-diameter blood vessels with a diameter less than 6 mm for which adequate substitutes still do not exist. One approach to vascular tissue engineering is to culture vascular cells on a scaffold in a bioreactor. The bioreactor establishes pseudophysiological conditions for culture (medium culture, 37°C, mechanical stimulation). Collagen gels are widely used as scaffolds for tissue regeneration due to their biological properties; however, they exhibit low mechanical properties. Mechanical characterization of these scaffolds requires establishing the conditions of testing in regard to the conditions set in the bioreactor. The effects of different parameters used during mechanical testing on the collagen gels were evaluated in terms of mechanical and viscoelastic properties. Thus, a factorial experiment was adopted, and three relevant factors were considered: temperature (23°C or 37°C), hydration (aqueous saline solution or air), and mechanical preconditioning (with or without). Statistical analyses showed significant effects of these factors on the mechanical properties which were assessed by tensile tests as well as stress relaxation tests. The last tests provide a more consistent understanding of the gels' viscoelastic properties. Therefore, performing mechanical analyses on hydrogels requires setting an adequate environment in terms of temperature and aqueous saline solution as well as choosing the adequate test.

Influence of different concentrations of fibrinogen on the properties of a fibrin matrix for vascular tissue engineering

2021 ◽  
Vol 29 (1) ◽  
pp. 21-34
Author(s):  
Vera G. Matveeva ◽  
Mariam Yu. Khanova ◽  
Tatyana V. Glushkova ◽  
Larisa V. Antonova
Keyword(s):  
Mechanical Properties ◽  
Tissue Engineering ◽  
Metabolic Activity ◽  
Vascular Tissue ◽  
Physical And Mechanical Properties ◽  
Vascular Tissue Engineering ◽  
Test Machine ◽  
Fibrin Matrix ◽  
Before And After ◽  
The Difference

Aim. To evaluate the potential utility of fibrin matrices containing 10, 20, and 25 mg/ml of fibrinogen (fibrin-10, fibrin-20, and fibrin-30, respectively) in vascular tissue engineering (VTE). Materials and Methods. Fibrinogen was isolated using the method of ethanol cryoprecipitation and polymerized using a solution of thrombin and CaCl2. The fibrin structure was studied in a scanning electron microscope, and the physical and mechanical properties of the material were tested on a Zwick/Roell test machine. The metabolic activity of endothelial cells (EC) on the fibrin surface was evaluated by the MTT assay, and the viability of fibroblasts in the thickness of fibrin and possibility for migration by in fluorescent and light microscopy. Percent of fibrin shrinkage was determined from the difference in the sample volumes before and after removal of moisture. Results. The fiber diameter did not differ among all fibrin samples, but the pore diameter in fibrin-30 was smaller than those in fibrin-10 and fibrin-20. A possibility for migration of fibroblasts into the depth of the fibrin matrix and preservation of 97-100% viability of cells at a depth 5 mm was confirmed. The metabolic activity of EC on the surface of fibrin-20 and fibrin-30 exceeded that on collagen, fibronectin, and fibrin-10. All fibrin samples shrank in volume to 95.5-99.5%, and the highest shrinkage was seen in fibrin-10. The physical and mechanical properties of fibrin were inferior to those of human A. mammaria by a factor of 10. Conclusion. Fibrin with fibrinogen concentrations of 20 and 30 mg/ml maintains a high metabolic and proliferative activity of EC on the surface and also a high viability of fibroblasts in the matrix. Its availability, ease of preparation, and a number of other favorable properties make fibrin a promising material for VTE. However, the problem of insufficient strength requires further investigations.

Elastin-Sprayed Tubular Scaffolds With Microstructures and Nanotextures for Vascular Tissue Engineering

2013 ◽  
Author(s):  
Jinah Jang ◽  
Junghyuk Ko ◽  
Dong-Woo Cho ◽  
Martin B. G. Jun ◽  
Deok-Ho Kim
Keyword(s):  
Tissue Engineering ◽  
Vascular Graft ◽  
Vascular Tissue ◽  
High Surface ◽  
Small Diameter ◽  
Vascular Tissue Engineering ◽  
Biophysical Properties ◽  
Fibrous Scaffold ◽  
Cardiovascular Tissue ◽  
Highly Porous

Development of a small-diameter vascular graft (<6 mm) have been challenging due to thrombosis and intimal hyperplasia [1]. To overcome this problem, cardiovascular tissue engineers have attempted to construct a highly porous and biocompatible fibrous scaffold providing a sufficient mechanical strength for the regeneration of a functional tissue [2–5]. Herein, we present a 3D tubular-shaped micro/nanofibrous composite-layered scaffold for vascular tissue engineering. The surface of scaffold has high surface roughness by introducing nanofibrous layer and the biophysical properties have been fulfilled by using microfibrous layer. Moreover, the atomized spraying technique is applied to spray elastin proteins, which is well known as an antithrombogenic material, on the surface of micro/nanofibrous composite-layered scaffold to introduce an appropriate antithrombogenic surface.

scholarly journals Vascular Tissue Engineering: Recent Advances in Small Diameter Blood Vessel Regeneration

2014 ◽  
Vol 2014 ◽  
pp. 1-27 ◽  
Author(s):  
Valentina Catto ◽  
Silvia Farè ◽  
Giuliano Freddi ◽  
Maria Cristina Tanzi
Keyword(s):  
Tissue Engineering ◽  
Cardiovascular Diseases ◽  
Blood Vessel ◽  
Polyethylene Terephthalate ◽  
Vascular Tissue ◽  
Vascular Grafts ◽  
Small Diameter ◽  
Synthetic Polymers ◽  
Vascular Tissue Engineering ◽  
Vessel Regeneration

Cardiovascular diseases are the leading cause of mortality around the globe. The development of a functional and appropriate substitute for small diameter blood vessel replacement is still a challenge to overcome the main drawbacks of autografts and the inadequate performances of synthetic prostheses made of polyethylene terephthalate (PET, Dacron) and expanded polytetrafluoroethylene (ePTFE, Goretex). Therefore, vascular tissue engineering has become a promising approach for small diameter blood vessel regeneration as demonstrated by the increasing interest dedicated to this field. This review is focused on the most relevant and recent studies concerning vascular tissue engineering for small diameter blood vessel applications. Specifically, the present work reviews research on the development of tissue-engineered vascular grafts made of decellularized matrices and natural and/or biodegradable synthetic polymers and their realization without scaffold.

scholarly journals Applying elastic fibre biology in vascular tissue engineering

2007 ◽  
Vol 362 (1484) ◽  
pp. 1293-1312 ◽  
Author(s):  
Cay M Kielty ◽  
Simon Stephan ◽  
Michael J Sherratt ◽  
Matthew Williamson ◽  
C. Adrian Shuttleworth
Keyword(s):  
Tissue Engineering ◽  
Vascular Graft ◽  
Vascular Tissue ◽  
Small Diameter ◽  
Elastic Fibre ◽  
Vascular Tissue Engineering ◽  
Western Society ◽  
Elastic Recoil ◽  
Vessel Structure ◽  
Biomaterial Scaffolds

For the treatment of vascular disease, the major cause of death in Western society, there is an urgent need for tissue-engineered, biocompatible, small calibre artery substitutes that restore biological function. Vascular tissue engineering of such grafts involves the development of compliant synthetic or biomaterial scaffolds that incorporate vascular cells and extracellular matrix. Elastic fibres are major structural elements of arterial walls that can enhance vascular graft design and patency. In blood vessels, they endow vessels with the critical property of elastic recoil. They also influence vascular cell behaviour through direct interactions and by regulating growth factor activation. This review addresses physiological elastic fibre assembly and contributions to vessel structure and function, and how elastic fibre biology is now being exploited in small diameter vascular graft design.

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