Biodegradable Stent with 3D-Printed Drug Layer
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Solution Overview
Problem
Conventional drug-releasing stents face challenges in accurately designing a drug release region, ensuring sufficient drug quantity, speed, and release time, while also providing effective luminal expansion and preventing stent movement.
Innovation Solution
A biodegradable stent combining a metal wire-based structure with a 3D-printed polymer structure, where the 3D-printed stent is inserted between two woven stent structures, allowing for a drug-coated outer layer and controlled drug release through differing biodegradation periods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a separate coating film is applied on a metal wire-based stent structure, then drug storage capacity is improved, but manufacturing complexity and difficulty of accurately designing the coating region increase
Solution Approach 1:
The patent merges the stent structure and drug storage function into a single integrated component. The stent wire itself is formed with a hollow cylindrical shape containing drug material, eliminating the need for separate coating films. This integration simplifies manufacturing while maintaining drug storage capacity and enabling precise control over the drug-release region through the stent's geometric design.
2Quantity of substance
If a biodegradable polymer forms the main wire framework, then drug quantity to lesion is improved, but luminal expansion capability and movement prevention deteriorate
Solution Approach 1:
The patent employs a composite structure combining metal wire (for mechanical strength and luminal expansion) with biodegradable polymer (for drug delivery). The metal wire framework provides the necessary structural integrity and expansion capability, while the biodegradable polymer coating or internal filling provides the drug quantity needed for lesion treatment. This composite approach allows both functions to coexist without compromising either.
3Adaptability or versatility
If a separate coating process is performed on the stent surface, then drug release function is added, but the quantity and release time control of drug deteriorate
Solution Approach 1:
The patent controls drug release parameters by changing the physical and chemical properties of the biodegradable polymer material. By selecting polymers with specific molecular weights, crystallinity, and degradation rates, the release time and quantity can be precisely controlled. The hollow cylindrical structure allows for optimized drug distribution and release kinetics, enabling better control over the therapeutic window compared to surface coating methods.
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 combination enables simultaneous luminal diameter restoration and targeted drug delivery, ensuring effective lesion treatment with controlled drug release patterns and minimized unnecessary drug application.
Implementation Method 1
a second stent structure which is a 3D print... by performing 3D printing using a printing material including a biodegradable polymer and a drug... the second stent structure is inserted into and disposed in a space between the first stent structure and the third stent structure
Implementation Method 2
a first stent structure which has a plurality of cells by means of a wire crossing pattern of a woven structure by weaving a metal wire made of a shape-memory alloy in a specific pattern on a jig
Data Source
Figure 1
Figure 2
Figure 3(a)~3(b)
AI summary
The present invention relates to a drug-releasing biodegradable stent comprising: a first stent structure having metal wires, which are formed from a shape memory alloy material, woven into a particular pattern on a jig, and thus having a plurality of cells by means of the crossing wires of the woven structure and formed in the shape of a hollow trunk; and a second stent structure which covers the outer peripheral side of the first stent structure or of which the outer peripheral side is covered by means of the first stent structure. The second stent structure is a 3D printed product which is formed in the shape of a hollow trunk and has a plurality of cells by means of crossing wires of a printed structure formed by means of 3D printing using a printing material comprising a biodegradable polymer and a drug.