Double-Layer Osteochondral Stent with Composite Interface
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Solution Overview
Problem
Current osteochondral tissue repair stents primarily focus on cartilage repair, neglecting the importance of subchondral bone regeneration, and face challenges in achieving a stable interface between different layers for effective multi-layer tissue repair.
Innovation Solution
A double-layer osteochondral tissue repair stent is developed using recombinant collagen, sodium hyaluronate, and hydroxyapatite, with varying concentrations and molecular weights, freeze-dried to form a gel-like structure, and crosslinked with 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride to enhance mechanical properties and biocompatibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single-layer cartilage repair stent is used, then cartilage defect repair is improved, but subchondral bone regeneration is neglected
Solution Approach 1:
The stent is divided into two distinct layers: a cartilage repair layer containing cartilage progenitor cells and a subchondral bone repair layer containing bone marrow mesenchymal stem cells. This segmentation allows each layer to independently perform its specific function while collectively addressing both cartilage and subchondral bone defects, resolving the contradiction between specialized cartilage repair and comprehensive multi-layer repair capability.
Solution Approach 2:
The stent employs composite material construction with the cartilage repair layer and subchondral bone repair layer having different compositions, porosity rates, and mechanical properties. The cartilage layer has higher porosity (80-95%) for cell infiltration, while the bone layer has lower porosity (50-70%) for structural support, creating a composite structure that simultaneously addresses both tissue types' repair requirements.
2Adaptability or versatility
If separate cartilage and bone repair layers are used, then multi-layer repair capability is improved, but interface stability between layers deteriorates
Solution Approach 1:
The cartilage repair layer and subchondral bone repair layer are merged into a single integrated stent structure with continuous porosity and interconnected pathways. The layers are combined such that the cartilage layer sits atop the bone layer, forming a unified composite structure that maintains interface stability while providing both multi-layer repair capability and structural integrity.
Solution Approach 2:
Different regions of the stent are given different local qualities: the cartilage repair layer has higher porosity and softer mechanical properties for cell infiltration and cartilage regeneration, while the subchondral bone repair layer has lower porosity and higher mechanical strength for structural support. This local differentiation maintains interface stability through graded transitions while enabling specialized functions in each layer.
3Strength
If high collagen concentration is used in the first feed solution, then cartilage layer structure is improved, but manufacturing complexity increases
Solution Approach 1:
The patent specifies precise parameter ranges for collagen concentration (90-120 mg/mL for the first feed solution, 60-90 mg/mL for the second feed solution) and sodium hyaluronate concentration (8-15 mg/mL) to optimize the gel-like structure formation. By controlling these parameters within defined ranges, the patent achieves optimal cartilage layer structure while maintaining manageable manufacturing complexity through standardized preparation protocols.
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 stent exhibits excellent mechanical properties, good biocompatibility, and a suitable degradation rate, allowing for effective repair of osteochondral tissue, with a high repair rate of osteochondral defects in animal models, demonstrating its efficacy in regenerating both cartilage and subchondral bone layers.
Implementation Method 1
Sodium hyaluronate based hydrogels are one of the most promising natural biomaterials for osteochondral tissue engineering
Implementation Method 2
freeze drying the first feed solution and the second feed solution to form a gel-like double-layer structure
Implementation Method 3
adding a crosslinking agent to the gel-like double-layer structure for crosslinking
Data Source
AI summary
Provided in the present application is a preparation method for a double-layer osteochondral tissue repair stent, comprising: formulating a first feed solution, the first feed solution comprising recombinant collagen, sodium hyaluronate, and hydroxyapatite; formulating a second feed solution, the second feed solution comprising recombinant collagen and sodium hyaluronate; freeze-drying the first feed solution and the second feed solution and forming a gel-like double-layer structure; and adding the gel-like double-layer structure into a crosslinking agent for crosslinking. The present method also relates to a double-layer osteochondral tissue repair stent, comprising: a first layer composed of raw materials including recombinant collagen, sodium hyaluronate, and hydroxyapatite; and a second layer composed of raw materials including recombinant collagen and sodium hyaluronate. The double-layer osteochondral tissue repair stent prepared by the present application has excellent mechanical properties, good biocompatibility, and a suitable degradation rate and, after degradation, the stent material can be reused as raw material for the formation of new bone, thus implementing osteochondral tissue repair.