Biodegradable Stent Inert Layers Control Degradation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Biodegradable medical devices often experience uncontrolled degradation, leading to reduced rigidity and strength, which can compromise their ability to sustain desired support in the body over time, particularly in applications like stents where continuous degradation weakens the device's ability to hold against arterial pressure.
Innovation Solution
A biodegradable medical device with multiple layers, including inert layers composed of lauric acid, which are designed to degrade in a controlled manner in response to external triggers or body fluids, allowing for sequential release of drugs and maintaining structural integrity through the use of biodegradable materials with varying degradation rates and glass transition temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If biodegradable medical devices are used to avoid long-term implantation issues, then the device will eventually degrade and be eliminated from the body, but the degradation occurs continuously and uncontrollably from the first day, resulting in reduced radial force and rigidity before the desired period
Solution Approach 1:
The biodegradable device is divided into multiple layers with different degradation characteristics. The outer layer degrades first to release drugs, while the inner layer maintains structural integrity and radial force for a longer period. This segmentation allows different parts of the device to serve different functions at different times, resolving the contradiction between duration of action and strength maintenance.
Solution Approach 2:
The patent utilizes changes in glass transition temperature (Tg) of polymeric materials to control degradation rates. By selecting polymers with specific Tg values, the device can maintain its glassy state and mechanical strength at body temperature while allowing controlled degradation. The parameter change in Tg enables the device to transition from a stable, strong state to a degrading state at a controlled pace.
2Strength
If non-biodegradable implantable medical devices are used to maintain continuous support, then the device remains in the patient's body throughout their life providing consistent strength, but it may cause untoward reactions and pose problems during interventional procedures
Solution Approach 1:
The patent employs biodegradable materials that serve as temporary, short-lived implants. These devices provide the necessary mechanical support during the critical healing period and then naturally degrade and are eliminated from the body. This approach replaces permanent implants with temporary ones, eliminating long-term harmful effects while maintaining short-term strength requirements.
Solution Approach 2:
The biodegradable device is designed to maintain its mechanical properties (strength, rigidity) during the initial period when support is needed, then undergo controlled parameter changes as it degrades. The material properties are engineered to provide high strength initially and then gradually decrease as the device is metabolized, mimicking the temporary support requirement without the long-term presence of foreign material.
3Duration of action of stationary object
If biodegradable materials with varying degradation rates are used to maintain structural integrity, then the device can sustain support for a longer period, but the complexity of controlling sequential degradation increases
Solution Approach 1:
The patent controls degradation timing by selecting polymers with specific glass transition temperatures (Tg). The outer layer uses a polymer with Tg below body temperature that degrades first, while the inner layer uses a polymer with Tg above body temperature that maintains strength and degrades later. This parameter-based control (Tg selection) provides a simple, elegant solution to sequential degradation control without complex mechanisms.
Solution Approach 2:
The device is constructed as a composite structure with multiple polymeric layers, each having different degradation characteristics. The outer layer comprises a first biodegradable polymer and the inner layer comprises a second biodegradable polymer with different Tg values. This composite material approach allows independent optimization of each layer's degradation profile while maintaining overall device functionality.
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
This approach enables controlled degradation and sustained drug release, maintaining the structural support and axial strength of biodegradable medical devices, such as stents, for a longer period, ensuring effective treatment and prevention of reoccurrence of diseases.
Implementation Method 1
The one or more inert layers are degraded in response to introduction of one or more external triggers when the implantable biodegradable medical device is placed within a living organism
Implementation Method 2
maintaining structural integrity through the use of biodegradable materials with varying degradation rates and glass transition temperatures
Data Source
Figure 1
Figure 2
AI summary
An implantable biodegradable device having two or more layers composed of one or more biodegradable materials is disclosed. The two or more layers are coated with one or more drugs. The implantable biodegradable device further having one or more inert layers is composed of a biodegradable material. The one or more inert layers of the implantable biodegradable device are degraded in response to introduction of one or more external triggers when the implantable biodegradable medical device is placed within a living organism. Further, a layer of the two or more layers having a position above an inert layer is degraded prior to degradation of the inert layer. Subsequently, a layer of the two or more layers having a position below the inert layer is degraded subsequent to degradation of the inert layer.