Biodegradable Stent Crystallinity Control
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Solution Overview
Problem
Current biodegradable stents lack sufficient strength and controlled degradation profiles, which can lead to inadequate support and persistence in the body lumens, necessitating improved fabrication methods to enhance their structural integrity and longevity.
Innovation Solution
The use of heat treatment to modify biodegradable polymers by controlling crystallinity, glass transition temperature, and molecular weight, allowing for enhanced strength and controlled biodegradation, with specific temperature and time parameters to achieve desired properties such as radial expansion and sustained support of body lumens.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If biodegradable polymers are used to make stents, then the stents can degrade over time in the body, but the stents lack sufficient strength and structural integrity
Solution Approach 1:
The patent applies heat treatment to change the physical and chemical parameters of the biodegradable polymer, specifically controlling crystallinity, glass transition temperature, and molecular weight. This transforms the polymer properties to achieve both sufficient strength for stent support and controlled degradation rates, resolving the contradiction between durability and biodegradability
Solution Approach 2:
The patent uses composite polymeric materials with controlled crystalline and amorphous phases. The crystalline regions provide structural strength and controlled degradation, while the amorphous regions allow for flexibility and radial expansion. This composite structure enables the stent to maintain strength during the required period while ensuring eventual biodegradation
2Strength
If heat treatment is applied to increase polymer crystallinity, then the stent strength increases, but the fabrication process becomes more complex
Solution Approach 1:
The patent performs heat treatment during the stent fabrication process itself, before implantation. By controlling crystallinity and other properties during manufacturing, the complex treatment is done in advance, simplifying the overall process while ensuring the stent has the required strength characteristics before being deployed in the body
3Ease of operation
If the stent is made to expand radially to support body lumens, then the stent provides adequate support, but the stent may fracture due to insufficient strength
Solution Approach 1:
The patent controls the glass transition temperature and molecular weight of the polymer through heat treatment. These parameter changes enable the stent to achieve adequate radial expansion at body temperature while maintaining sufficient strength and fracture resistance, as the polymer transitions from a glassy to a rubbery state allowing expansion without breaking
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The treated biodegradable stents exhibit improved radial strength and controlled expansion, maintaining structural integrity for extended periods while ensuring biodegradation, thus providing effective support to body lumens without fracture.
Implementation Method 1
The use of heat treatment to modify biodegradable polymers by controlling crystallinity, glass transition temperature, and molecular weight
Implementation Method 2
controlling crystallinity
Implementation Method 3
glass transition temperature
Implementation Method 4
biodegradable polymers which degrade by hydrolysis and other reaction mechanisms in the vascular or other luminal environment over time
Data Source
AI summary
The disclosure provides biodegradable implantable devices such as a stent comprising a biodegradable polymeric wherein the polymeric material is treated to control crystallinity and/or Tg. The stent is capable to expand at body temperature from a crimped configuration to a deployed diameter and have sufficient strength to support a body lumen.