Investigation of 3-D mechanical properties of blood vessels using a new in vitro tests system: results on sheep common carotid arteries

2001 ◽  
Vol 48 (4) ◽  
pp. 442-451 ◽  
Author(s):  
W.C.P.M. Blondel ◽  
J. Didelon ◽  
G. Maurice ◽  
J.-P. Carteaux ◽  
Xiong Wang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Blood Vessels ◽  
Carotid Arteries ◽  
In Vitro Tests ◽  
Common Carotid Arteries

3D-printing of Urethane-based Photoelastomers for Vascular Tissue Regeneration

2009 ◽  
Vol 1239 ◽  
Author(s):  
Stefan Baudis ◽  
Thomas Pulka ◽  
Bernhard Steyrer ◽  
Harald Wilhelm ◽  
Guenter Weigel ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Blood Vessels ◽  
Vascular Tissue ◽  
Mechanical Performance ◽  
In Vitro Tests ◽  
Layer By Layer ◽  
Digital Light Processing ◽  
Tissue Replacement ◽  
Tear Resistance

AbstractThe mechanical properties of materials designated for vascular tissue replacement are of crucial importance. The elastic modulus, the tensile strength as well as the suture tear resistance have to be adjusted. Our approach is to use photopolymers for artificial vascular grafts. Via the layer-by-layer photopolymerization of suitable resin formulations as performed in additive manufacturing (AM) very complex structures are realizable. Hence AM offer the possibility to create cellular structures within the artificial grafts that might favor the ingrowth of new tissue. Commercially available urethane acrylates (UA) were chosen as base monomers since urethane groups are known to have good cell-adhesion behavior and poly-UAs show adequate mechanical performance. The mechanical properties of the photoelastomers can be tailored by addition of reactive diluents (e.g. 2-hydroxyethyl acrylate, HEA) and thiols (e.g. 3,6 dioxa-1,8-octane-dithiol) as chain transfer agents to comply with the mechanical properties of natural blood vessels. To examine the suture tear resistance a new testing method has been developed. Finally, a formulation containing 30 wt% UA and 70 wt% HEA complies with the mechanical properties of natural blood vessels, shows good biocompatibility in in-vitro tests and was successfully 3D-printed with digital light processing AM.

scholarly journals Goldmann Tonometry and Corneal Biomechanics

2021 ◽  
Vol 11 (9) ◽  
pp. 4025
Author(s):  
Dario Messenio ◽  
Marco Ferroni ◽  
Federica Boschetti
Keyword(s):  
Mechanical Properties ◽  
Anterior Chamber ◽  
Pressure Transducer ◽  
Pearson Correlation ◽  
Corneal Thickness ◽  
Applanation Tonometry ◽  
In Vitro Tests ◽  
Goldmann Tonometry ◽  
The Difference

Glaucoma is the second cause of irreversible blindness in the world. Intraocular pressure (IOP) is a recognized major risk factor for the development and progression of glaucomatous damage. Goldmann applanation tonometry (GAT) is internationally accepted as the gold standard for the measurement of IOP. The purpose of this study was to search for correlations between Goldmann tonometry and corneal mechanical properties and thickness by means of in vitro tests. IOP was measured by the Goldmann applanation tonometer (GIOP), and by a pressure transducer inserted in the anterior chamber of the eye (TIOP), at increasing pressure levels by addition of saline solution in the anterior chamber of enucleated pig eyes (n = 49). Mechanical properties were also determined by inflation tests. The GAT underestimated the real measurements made by the pressure transducer, with most common differences in the range 15–28 mmHg. The difference between the two instruments, highlighted by the Bland–Altman test, was confirmed by ANOVA, normality tests, and Mann–Whitney’s tests, both on the data arranged for infusions and for the data organized by pressure ranges. Pearson correlation tests revealed a negative correlation between (TIOP-GIOP) and both corneal stiffness and corneal thickness. In conclusion, data obtained showed a discrepancy between GIOP and TIOP more evident for softer and thinner corneas, that is very important for glaucoma detection.

Role of pH on stability and mechanical properties of gelatin films

2012 ◽  
Vol 27 (1) ◽  
pp. 67-77 ◽  
Author(s):  
Michela Gioffrè ◽  
Paola Torricelli ◽  
Silvia Panzavolta ◽  
Katia Rubini ◽  
Adriana Bigi
Keyword(s):  
Mechanical Properties ◽  
Young’S Modulus ◽  
Triple Helix ◽  
Young's Modulus ◽  
In Vitro Tests ◽  
Diffraction Reflection ◽  
X Ray Diffraction ◽  
Solution Ph ◽  
Gelatin Films

The effect of the film-forming solution pH on the triple-helix content, thermal stability, and mechanical properties of gelatin films was investigated. The films were prepared from solutions at different pHs of type A pigskin gelatin, and their mechanical characteristics were determined. At pHs higher than 9 and lower than 5, Young’s modulus, E, and the stress at break, σb, of the films decreased significantly. Cross-linking with genipin reduced deformation at break, ϵb, and increased Young’s modulus. The intensity of the 1.1-nm X-ray diffraction reflection and the denaturation enthalpy decreased at these pHs, indicating that the triple helix reduced. Preliminary in vitro tests on the cross-linked samples indicated good cell proliferation and viability.

scholarly journals Flow-Induced Changes in Dimensions and Mechanical Properties of Rabbit Common Carotid Arteries

2005 ◽  
Vol 48 (4) ◽  
pp. 477-483 ◽  
Author(s):  
Takeo MATSUMOTO ◽  
Eijiro OKUMURA ◽  
Takahiro SHIRONO ◽  
Eiketsu SHO ◽  
Hirotake MASUDA ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Carotid Arteries ◽  
Induced Changes ◽  
Common Carotid Arteries

Influence of the Crosshead Rate on the Mechanical Properties of Fixation Systems of ACL Tendon Grafts

2009 ◽  
Vol 25 (4) ◽  
pp. 313-321 ◽  
Author(s):  
Oscar Martel ◽  
Juan F. Cárdenes ◽  
Gerardo Garcés ◽  
José A. Carta
Keyword(s):  
Mechanical Properties ◽  
Cruciate Ligament ◽  
Testing Machine ◽  
Interference Screw ◽  
In Vitro Tests ◽  
Biomechanical Test ◽  
Pull Out ◽  
Fixation Devices ◽  
Tendon Grafts

Anterior cruciate ligament (ACL) reconstruction is one of the most important aspects of knee surgery. For this purpose, several fixation devices have been developed, although the interference screw is the most frequently used. The most typical biomechanical test of these devices consists of placing them in a testing machine and subjecting them to a pull-out test. However, insufficient attention has been paid to the influence of the displacement test rate on the mechanical properties of the fixation system. The aim of this study is to compare the influence of the crosshead rate in the biomechanical test of two different devices for the fixation of ACL tendon grafts. One hundred in vitro tests were performed using porcine tibiae and bovine tendons. The fixation devices used were (1) an interference screw and (2) a new expansion device. All ACL reconstructions were subjected to pull-out test to failure. Five crosshead rates were employed in a range from 30 mm/min to 4000 mm/min. Statistical analyses of the results show that, for the two devices, the rate has a significant effect on both maximum force and stiffness. Moreover, the new expansion device showed lesser dependency on the crosshead rate than the interference screw.

Remodeling of the Constitutive Equation While a Blood Vessel Remodels Itself Under Stress

1993 ◽  
Vol 115 (4B) ◽  
pp. 453-459 ◽  
Author(s):  
Y. C. Fung ◽  
S. Q. Liu ◽  
J. B. Zhou
Keyword(s):  
Mechanical Properties ◽  
Blood Vessel ◽  
Blood Vessels ◽  
Vessel Wall ◽  
Elastic Strain Energy ◽  
Growth Stress ◽  
Elastic Behavior ◽  
Stress Strain

Changes in the mechanical properties of a blood vessel when it remodels itself under stress are reviewed. One of the recent findings about blood vessels is the rapidity of tissue remodeling when the blood pressure is changed. When the tissue structure and material composition remodel, the zero-stress state of the vessel changes. The mechanical properties change also in the remodeling process. If the elastic behavior is expressed in terms of a pseudo-elastic strain-energy function, then the constants in the function will change in the course of the remodeling. With all these changes taking place, the scope of constitutive equations broadens: it should now include a mass-and-structure growth-stress relationship as well as a stress-strain-relationship. To obtain the mass-and-structure growth-stress relationship, one must be able to determine the mechanical properties of the different layers of the vessel wall, as well as the chemical composition and morphology. For the blood vessels, new methods of mechanical testing must be introduced. A key thought is to use bending of the blood vessel wall. By bending, different layers of the vessel wall are subjected to different stresses, leading to equations that can be used to solve the inverse problem of determining the stress-strain law from measured stress and strain. In vitro and in vivo experiments and theoretical prospectives are presented.

The mechanical properties of exposed human common carotid arteries in vivo

1979 ◽  
Vol 74 (5) ◽  
pp. 545-554 ◽  
Author(s):  
R. Busse ◽  
R. D. Bauer ◽  
A. Schabert ◽  
Y. Summa ◽  
P. Bumm ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Carotid Arteries ◽  
Common Carotid Arteries

Experimental Investigation of Collagen Waviness and Orientation in Adventitia of Common Carotid Arteries of Rabbits

2012 ◽  
Author(s):  
Aristotelis Agianniotis ◽  
Nikos Stergiopulos
Keyword(s):  
Mechanical Properties ◽  
Structural Organization ◽  
Collagen Fiber ◽  
Carotid Arteries ◽  
Collagen Fibers ◽  
Angular Dispersion ◽  
Fluorescent Marker ◽  
Outermost Layer ◽  
Common Carotid Arteries ◽  
Fiber Organization

The adventitia is the outermost layer of blood vessels and its mechanical properties are determined by the organization of collagen fibers in this layer. The waviness and the angular dispersion characterize the collagen fiber organization. Previous studies were mainly conducted on loaded and chemically fixed vessels, which could modify the structural organization [1]. We have combined fluorescent marker with confocal microscopy and image analysis to quantify the waviness and angular distribution of collagen fibers, and determine the correlation between the waviness distribution of fibers and their main orientation in the adventitia of rabbit common carotid arteries at their zero-stress state.

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