Engineered valve and method of making
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Solution Overview
Problem
There is a lack of a clinically available prosthetic vein valve that is non-thrombogenic and can withstand the lower blood flow rates in the leg, and existing materials for vein valve leaflets lack stability and hemocompatibility, leading to challenges in treating chronic venous insufficiency and venous ulcers.
Innovation Solution
A biologically engineered valve with an embedded Nitinol stent and endothelialization potential, featuring a matrix with embedded leaflets, which is remodeled from hydrogels like fibrin and collagen, and can withstand back pressures over 300 mmHg, eliminating the need for stitching and ensuring compatibility with venous systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional prosthetic valve materials are used, then structural strength is achieved, but hemocompatibility and stability are insufficient leading to thrombosis
Solution Approach 1:
The invention uses a composite structure combining a biocompatible polymer matrix (such as fibrin, collagen, or hyaluronan) with an embedded Nitinol stent. The polymer matrix provides hemocompatibility and endothelialization potential, while the Nitinol stent provides structural strength and radial support. This composite approach resolves the contradiction by integrating materials that individually address different requirements.
Solution Approach 2:
The invention changes the material parameters by using natural polymers with specific mechanical and biological properties. The polymer matrix is engineered to have appropriate elasticity, porosity, and biochemical composition to promote endothelial cell attachment and growth, thereby improving hemocompatibility while maintaining structural integrity through the embedded stent.
2Reliability
If existing vein valve materials are used, then ease of manufacture is maintained, but stability and durability are insufficient
Solution Approach 1:
The combination of polymer matrix and Nitinol stent creates a composite structure where the stent provides long-term structural stability and durability, while the polymer matrix provides biological stability through endothelialization. This composite approach ensures both immediate structural integrity and long-term functional stability.
Solution Approach 2:
The polymer matrix is designed to support in-situ endothelialization, where the body's own endothelial cells migrate and cover the implant surface. This self-service mechanism improves long-term stability by creating a biocompatible interface that reduces inflammation and thrombosis risk, thereby enhancing durability without requiring additional manufacturing complexity.
3Stress or pressure
If a prosthetic valve is designed to withstand high back pressure, then pressure resistance is improved, but the valve may not accommodate lower blood flow rates in the leg
Solution Approach 1:
The valve design incorporates dynamic leaflets made from the polymer matrix that can adapt their shape and opening angle in response to varying flow conditions. The embedded Nitinol stent provides a flexible yet supportive framework that maintains structural integrity under high back pressure while allowing the leaflets to move freely to accommodate low flow rates in the venous system.
Solution Approach 2:
The valve geometry parameters are optimized for venous flow characteristics, with leaflet dimensions and stent radial strength tuned to withstand venous back pressure while maintaining low resistance to forward flow. The polymer matrix properties are adjusted to provide appropriate leaflet flexibility for low-flow conditions while the Nitinol stent ensures structural stability under pressure.
4Reliability
If a complex valve structure is created to improve function, then performance is enhanced, but manufacturing complexity increases
Solution Approach 1:
The Nitinol stent is pre-formed with the desired three-dimensional configuration and radial strength characteristics before being embedded in the polymer matrix. This preliminary action simplifies the overall manufacturing process by eliminating the need for complex post-assembly steps to achieve proper valve geometry and structural support.
Solution Approach 2:
The invention merges the structural support function (Nitinol stent) with the valve leaflet function (polymer matrix) into a single integrated construct. The stent is embedded within the polymer matrix during a single manufacturing step, combining what would otherwise be separate assembly operations into one unified process, thereby reducing manufacturing complexity while maintaining functional performance.
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 engineered valve exhibits low open valve pressure drop, small closing volume, and durability of one million cycles, demonstrating physiological compliance and tensile mechanical properties comparable to native cardiovascular tissue, with potential for endothelialization and recellularization.
Implementation Method 1
An engineered valve includes an embedded support structure. In one embodiment, the support structure is a Nitinol stent.
Implementation Method 2
Representative polymers include, without limitation, agarose, methylcellulose, hyaluronan, collagen, fibrin, fibrinogen, and combinations thereof. In some embodiments, the polymer is a hydrogel.
Implementation Method 3
the method further comprises culturing the tubular structure comprising the support structure under conditions in which the hydrogel comprising the matrix-producing cells is remodeled into a tubular extracellular matrix comprising the support structure at the first end
Implementation Method 4
A biologically engineered valve with an embedded Nitinol stent and endothelialization potential
Data Source
AI summary
This disclosure provides a tissue-engineered transcatheter vein valve and methods of making such a tissue-engineered transcatheter vein valve. Methods of making the valve include casting or molding a polymer into a tubular structure having a first end and a second end, where the first end of the tubular structure is cast or molded around a tubular support structure and where the second end of the tubular structure is cast or molded in the absence of the support structure; everting the polymer at the second end through the support structure; anchoring the second end of the tubular structure to the support structure at a first position and a second position, where the anchored first position and the anchored second position result in commissures, forming leaflets therebetween.