Preparation and In Vitro Degradation of PDO Intravascular Stents with Braided Structure

In this paper, in vitro degradation behaviors of the PDO monofilaments and the stents were studied. The mechanical properties,morphology observation and Differential Scanning Calorimeter (DSC) of PDO monofilaments were determined, as well as the compression strength of the stents. The experimental results showed that the PDO monofilaments contained half of its original strength after 6 weeks degradation and lost its strength in the 10thweek. DSC outcomes showed that the crystalline regions of PDO havent been hydrolyzed after 16 weeks of degradation. The stents demonstrated good compression behaviors for 12 weeks and therefore can be utilized in short-term application.

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In Vitro Degradation Behaviours of PDO Monofilament and Its Intravascular Stents with Braided Structure

Autex Research Journal ◽

10.1515/aut-2015-0031 ◽

2016 ◽

Vol 16 (2) ◽

pp. 80-89 ◽

Cited By ~ 8

Author(s):

Cong-er Wang ◽

Pei-hua Zhang

Keyword(s):

Mechanical Properties ◽

Vascular Wall ◽

Radial Force ◽

Temporary Increase ◽

Crystalline Region ◽

Bending Rigidity ◽

Intravascular Stents ◽

Braided Structure ◽

Intravascular Stent

Abstract Biodegradable intravascular stent has attracted more and more focus in recent years as an effective solution for angiostenosis. Ideal stents were expected to exhibit sufficient radial force to support the vascular wall, while suitable flexibility for the angioplasty. After vascular remodeling, stents should be degraded into small molecular and be eliminated from human body, causing no potential risk. In this paper, poly-p-dioxanone (PDO) monofilament was braided into net structure with four different braiding density, two of which exhibited sufficient radial force larger than 30 kPa, and three of which showed the bending rigidity within 11.7–88.1 N•mm2. The degradation behaviors of monofilaments and stents have been observed for 16 weeks. The findings obtained indicate that degradation first occurred in morphology region, which induced temporary increase of crystallinity, monofilament bending rigidity and stent mechanical properties. During this period, monofilament tends to be hard and brittle and lost its tensile properties. Then the crystalline region was degraded and stent mechanical properties decreased. All the results reveal that the PDO intravascular stents with braided structure were able to afford at least 10 weeks of sufficient support to the vascular wall.

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Comparing the mechanical properties, microstructure, texture and in-vitro degradation behavior of TNTZ/nano-fluorapatite composite and TNTZ bioalloy

Journal of the Mechanical Behavior of Biomedical Materials ◽

10.1016/j.jmbbm.2021.104402 ◽

2021 ◽

Vol 117 ◽

pp. 104402

Author(s):

F. Rajabi ◽

A. Zarei-Hanzaki ◽

H.R. Abedi ◽

A. Safdel ◽

E. Bertrand

Keyword(s):

Mechanical Properties ◽

Degradation Behavior ◽

In Vitro Degradation

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Mechanical properties and in vitro degradation of bioresorbable knitted stents

Journal of Biomaterials Science Polymer Edition ◽

10.1163/15685620260449714 ◽

2002 ◽

Vol 13 (12) ◽

pp. 1313-1323 ◽

Cited By ~ 24

Author(s):

Juha-Pekka Nuutinen ◽

Tero Välimaa ◽

Claude Clerc ◽

Pertti Törmälä

Keyword(s):

Mechanical Properties ◽

In Vitro Degradation

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Effects of Cyclic Stress on the Mechanical Properties of Cultured Collagen Fascicles from the Rabbit Patellar Tendon

Journal of Biomechanical Engineering ◽

10.1115/1.1634286 ◽

2003 ◽

Vol 125 (6) ◽

pp. 893-901 ◽

Cited By ~ 21

Author(s):

Ei Yamamoto ◽

Susumu Tokura ◽

Kozaburo Hayashi

Keyword(s):

Mechanical Properties ◽

Tensile Strength ◽

Patellar Tendon ◽

Control Level ◽

Quadratic Function ◽

Peak Stress ◽

Cyclic Stress ◽

Original Strength

Effects of cyclic stress on the mechanical properties of collagen fascicles were studied by in vitro tissue culture experiments. Collagen fascicles (approximately 300 μm in diameter) obtained from the rabbit patellar tendon were applied cyclic load at 4 Hz for one hour per day during culture period for one or two weeks, and then their mechanical properties were determined using a micro-tensile tester. There was a statistically significant correlation between tensile strength and applied peak stress in the range of 0 to 5 MPa, and the relation was expressed by a quadratic function. The maximum strength (19.4 MPa) was obtained at the applied peak stress of 1.8 MPa. The tensile strength of fascicles were within a range of control values, if they were cultured under peak stresses between 1.1 and 2.6 MPa. Similar results were also observed in the tangent modulus, which was maintained at control level under applied peak stresses between 0.9 and 2.8 MPa. The stress of 0.9 to 1.1 MPa is equivalent to approximately 40% of the in vivo peak stress which is developed in the intact rabbit patellar tendon by running, whereas that of 2.6 to 2.8 MPa corresponds to approximately 120% of the in vivo peak stress. Therefore, the fascicles cultured under applied peak stresses of lower than 40% and higher than 120% of the in vivo peak stress do not keep the original strength and modulus. These results indicate that the mechanical properties of cultured collagen fascicles strongly depend upon the magnitude of the stress applied during culture, which are similar to our previous results observed in stress-shielded and overstressed patellar tendons in vivo.

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