Photodegradable Layer for Controlled Stent Biodegradation
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Solution Overview
Problem
Biodegradable intraluminal stents face challenges in controlling the rate of mass loss and mechanical strength due to unregulated biodegradation when in contact with bodily fluids, leading to premature loss of patency in body lumens.
Innovation Solution
A hybrid stent design featuring a biodegradable tubular body with a photodegradable layer that remains chemically inert to bodily fluids until activated by UV light, delaying the biodegradation of the stent until its patency is no longer required, thereby maintaining mechanical strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of repair
If a biodegradable material is used for the stent body, then the stent can be removed naturally after serving its purpose, but the stent loses mass prematurely due to uncontrolled biodegradation when contacting bodily fluids
Solution Approach 1:
A photodegradable layer is introduced as an intermediary protective barrier between the biodegradable stent body and the bodily fluids. This layer prevents direct contact and uncontrolled biodegradation initially, then can be selectively removed via UV light activation to allow controlled biodegradation when needed, thus mediating between the need for natural removal and mass loss control
2Object-affected harmful factors
If the stent is made fully biodegradable, then adverse risks from long-term presence are reduced, but the mechanical strength is insufficient to maintain patency for the intended time frame
Solution Approach 1:
The stent is constructed as a composite structure combining a biodegradable stent body with a photodegradable protective layer. The photodegradable layer provides enhanced mechanical protection and chemical inertness during the critical patency maintenance period, while the biodegradable body provides the necessary mechanical strength. This composite approach allows the stent to maintain strength when needed while ultimately degrading to reduce long-term adverse risks
3Duration of action of moving object
If the photodegradable layer is activated early, then biodegradation begins sooner, but the stent loses mechanical strength before it is needed
Solution Approach 1:
The photodegradable layer is prepared in advance as a protective barrier that can be activated on demand. By using UV light activation, the system allows preliminary preparation of the stent with the protective layer intact, then activates biodegradation only when the clinical situation requires it, thus controlling the timing to maintain strength when needed while enabling degradation when patency is no longer required
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 hybrid stent effectively delays biodegradation until necessary, ensuring sustained patency of the body lumen and eliminating the need for additional removal procedures by allowing controlled degradation of the photodegradable layers.
Implementation Method 1
The photodegradable layer is selectively adapted to be activated from a chemically inert state to a photodegradable state. The photodegradable state initiates degradation of the photodegradable layer so as to expose at least a portion of the biodegradable material
Implementation Method 2
The fiber section is adapted to propagate UV light from the proximal section to the distal section and thereafter irradiate UV light from the distal section to the photodegradable material
Data Source
Figure 1A~1B
Figure 2A~2C
Figure 3A~3C
AI summary
An intraluminal device with controlled biodegradation is provided. The intraluminal device comprises a biodegradable tubular main body. An outer photodegradable layer is disposed over at least a portion of the intraluminal device. The photodegradable outer layer is chemically inert to the body fluids of the implanted region, thereby preventing premature biodegradation of the stent. Degradation of the outer photodegradable layer after a predetermined time occurs by irradiating the layer with UV light waves. After removal of the outer photodegradable layer, the tubular main body becomes exposed to the in vivo environment, thereby allowing biodegradation of the tubular main body.