Three-Layer Vascular Graft Structure for Compliance and Cell Infiltration
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Solution Overview
Problem
Existing vascular grafts face limitations such as limited tissue availability, inadequate performance, donor-site morbidity, thrombogenicity, and intimal hyperplasia, with current synthetic and biologic grafts failing to adequately mimic native tissue structure and function.
Innovation Solution
A biohybrid, three-layered graft design combining ECM gel layers with biodegradable polymer matrices to replicate native tissue functional heterogeneity, using electrospinning and TIPS to create a tubular structure that mimics the native blood vessel anatomy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If non-degradable materials such as PET and ePTFE are used for vascular grafts, then the grafts have extended half-life, but they require daily anticoagulation therapy and induce mechanical mismatch at the prosthesis-tissue interface
Solution Approach 1:
The patent changes the material parameter from non-degradable to biodegradable polymers, which eliminates the need for daily anticoagulation therapy and reduces mechanical mismatch. The biodegradable nature allows the graft to gradually integrate with host tissue, transforming the long-term persistence issue into a controlled degradation process that improves biocompatibility while maintaining structural integrity during the critical healing period.
Solution Approach 2:
The patent employs composite material structures combining biodegradable polymer matrices with ECM gel layers. This composite approach integrates the mechanical strength of synthetic polymers with the bioactivity of ECM components, achieving both extended functional performance and reduced thrombogenicity through the synergistic combination of material properties.
2Reliability
If biologic tissue based grafts are used, then advantages in bioactivity are introduced, but control over device structure and function is partial due to dependence on tissue source and decellularization protocol
Solution Approach 1:
The patent uses synthetic biodegradable polymer matrices that are designed to mimic and copy the structural and functional properties of native ECM. This copying approach allows reproduction of the beneficial bioactive features of biologic tissue while eliminating the variability and complexity associated with different tissue sources and decellularization protocols, achieving consistent control over device structure and function.
Solution Approach 2:
The patent segments the graft into distinct functional layers (inner layer, middle layer, outer layer) with specific compositions and properties. This segmentation allows independent optimization of each layer's characteristics, providing precise control over overall device structure and function while maintaining the bioactivity benefits of ECM-like materials in each specific functional zone.
3Manufacturing precision
If electrospinning, TIPS or particulate leaching are used to prepare TEVG, then capacity to tune graft morphology is improved, but bioactivity of processed synthetic materials is limited when compared to biologic material based grafts
Solution Approach 1:
The patent creates composite structures where synthetic biodegradable polymer matrices (processed by electrospinning, TIPS, or particulate leaching) are combined with ECM gel layers. This composite approach maintains the manufacturing precision and morphology control advantages of synthetic materials while introducing the bioactivity of ECM components, achieving both tuned graft morphology and enhanced bioactivity.
Solution Approach 2:
The ECM gel layer acts as an intermediary between the synthetic polymer matrix and the host tissue. It mediates the interaction by providing bioactive signals and cues that promote cell infiltration and tissue integration, thereby enhancing the bioactivity of the otherwise synthetic graft material while maintaining the structural benefits of the processed synthetic matrix.
4Shape
If three-layered structure is fabricated by cell sheets apposition, then native tissue structure is mimicked, but high cost and long processing time are required
Solution Approach 1:
The patent uses synthetic biodegradable polymer matrices that are engineered to copy and replicate the three-layered structure of native blood vessels. This copying approach achieves native tissue structure mimicry through controlled manufacturing processes, eliminating the need for time-consuming cell sheet apposition while maintaining the beneficial structural heterogeneity of native vessels.
Solution Approach 2:
The patent incorporates ECM gel layers into the scaffold structure during the manufacturing process itself, rather than requiring subsequent lengthy cell culture and tissue formation steps. This preliminary action of pre-integrating bioactive ECM components allows the graft to be implanted in a ready-to-function state, dramatically reducing processing time while maintaining native tissue structure mimicry.
5Strength
If non-porous nondegradable structure is used, then structural strength is maintained, but host cell infiltration is reduced
Solution Approach 1:
The patent employs porous biodegradable polymer matrices that provide both structural strength and enhanced host cell infiltration. The porous structure allows cells to penetrate and populate the graft material, while the biodegradable nature ensures that the structural integrity is maintained during the critical early period and then gradually transferred to the host tissue as degradation occurs.
Solution Approach 2:
The patent changes the material parameters from nondegradable to biodegradable and from non-porous to porous, creating a dynamic structure that provides initial structural strength through the intact porous matrix, then progressively degrades to allow complete host cell infiltration and tissue replacement. This parameter transformation resolves the contradiction between maintaining strength and enabling cell infiltration.
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 grafts achieve physiologically relevant mechanical compliance and host cell infiltration, providing a scalable and functional vascular replacement with improved biocompatibility and reduced thrombogenicity.
Implementation Method 1
using electrospinning and TIPS to create a tubular structure that mimics the native blood vessel anatomy
Implementation Method 2
using electrospinning and TIPS to create a tubular structure that mimics the native blood vessel anatomy
Data Source
AI summary
A multi-layer device is provided that is useful in tissue regeneration, for example, for vascular regeneration, e.g., for use in treatment of a coronary vascular disease, such as for treatment of myocardial infarction. A method of making the device also is provided.