Understanding how polymers such as PLLA degrade in vivo will enhance biodegradable stent design. This study examined the effect of static and dynamic loads on PLLA stent fibers in vitro. The stent fibers (generously provided by TissueGen, Inc.) were loaded axially with 0 N, 0.5 N, 1 N, or 0.125–0.25 N (dynamic group, 1 Hz) and degraded in PBS at 45 °C for an equivalent degradation time of 15 months. Degradation was quantified through changes in tensile mechanical properties. The mechanical behavior was characterized using the Knowles strain energy function and a degradation model. A nonsignificant increase in fiber stiffness was observed between 0 and 6 months followed by fiber softening thereafter. A marker of fiber softening, β, increased between 9 and 15 months in all groups. At 15 months, the β values in the dynamic group were significantly higher compared to the other groups. In addition, the model indicated that the degradation rate constant was smaller in the 1-N (0.257) and dynamic (0.283) groups compared to the 0.5-N (0.516) and 0-N (0.406) groups. While the shear modulus fluctuated throughout degradation, no significant differences were observed. Our results indicate that an increase in static load increased the degradation of mechanical properties and that the application of dynamic load further accelerated this degradation.
Skip Nav Destination
Article navigation
August 2014
Research-Article
The Effect of Static and Dynamic Loading on Degradation of PLLA Stent Fibers
Danika Hayman,
Danika Hayman
Department of Bioengineering,
e-mail: danika.hayman@imperial.ac.uk
Imperial College of London
,South Kensington Campus
,London SW7 2AZ
, UK
e-mail: danika.hayman@imperial.ac.uk
Search for other works by this author on:
Christie Bergerson,
Christie Bergerson
Department of Biomedical Engineering,
e-mail: cmbergerson@gmail.com
Texas A&M
,College Station, TX 77843
e-mail: cmbergerson@gmail.com
Search for other works by this author on:
Samantha Miller,
Samantha Miller
Department of Biomedical Engineering,
Texas A&M
,College Station, TX 77843
Search for other works by this author on:
Michael Moreno,
Michael Moreno
Department of Biomedical Engineering,
e-mail: mmoreno@bme.tamu.edu
Texas A&M
,College Station, TX 77843
e-mail: mmoreno@bme.tamu.edu
Search for other works by this author on:
James E. Moore
James E. Moore
1
Department of Bioengineering,
e-mail: james.moore.jr@imperial.ac.uk
Imperial College of London
,South Kensington Campus
,London SW7 2AZ
, UK
e-mail: james.moore.jr@imperial.ac.uk
1Corresponding author.
Search for other works by this author on:
Danika Hayman
Department of Bioengineering,
e-mail: danika.hayman@imperial.ac.uk
Imperial College of London
,South Kensington Campus
,London SW7 2AZ
, UK
e-mail: danika.hayman@imperial.ac.uk
Christie Bergerson
Department of Biomedical Engineering,
e-mail: cmbergerson@gmail.com
Texas A&M
,College Station, TX 77843
e-mail: cmbergerson@gmail.com
Samantha Miller
Department of Biomedical Engineering,
Texas A&M
,College Station, TX 77843
Michael Moreno
Department of Biomedical Engineering,
e-mail: mmoreno@bme.tamu.edu
Texas A&M
,College Station, TX 77843
e-mail: mmoreno@bme.tamu.edu
James E. Moore
Department of Bioengineering,
e-mail: james.moore.jr@imperial.ac.uk
Imperial College of London
,South Kensington Campus
,London SW7 2AZ
, UK
e-mail: james.moore.jr@imperial.ac.uk
1Corresponding author.
Manuscript received November 14, 2013; final manuscript received April 11, 2014; accepted manuscript posted May 8, 2014; published online June 3, 2014. Assoc. Editor: Sean S. Kohles.
J Biomech Eng. Aug 2014, 136(8): 081006 (9 pages)
Published Online: June 3, 2014
Article history
Received:
November 14, 2013
Revision Received:
April 11, 2014
Accepted:
May 8, 2014
Citation
Hayman, D., Bergerson, C., Miller, S., Moreno, M., and Moore, J. E. (June 3, 2014). "The Effect of Static and Dynamic Loading on Degradation of PLLA Stent Fibers." ASME. J Biomech Eng. August 2014; 136(8): 081006. https://doi.org/10.1115/1.4027614
Download citation file:
Get Email Alerts
Related Articles
Modeling of Deformation-Accelerated Breakdown of Polylactic Acid Biodegradable Stents
J. Med. Devices (December,2010)
Concept Selection in the Development of Medical Devices: The Case of the Smart Stent-Graft
J. Med. Devices (June,2011)
Laser-Optic Evaluation for Bond Quality of Polymeric Medical Tubing
J. Pressure Vessel Technol (August,2002)
Related Proceedings Papers
Related Chapters
Structure, Properties, and Applications of Plastics
Introduction to Plastics Engineering
mDFA Human Empirical Results
Modified Detrended Fluctuation Analysis (mDFA)
Changes in Surface Morphology and Microcrack Initiation in Polymers Under Simultaneous Exposure to Stress and Fast Atom Bombardment
Influence of Radiation on Material Properties: 13th International Symposium (Part II)