CUPE Scaffold Sheet Engineering for Vascular Grafts
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current biomaterials and scaffolds for soft tissue engineering, particularly for small diameter blood vessels, face challenges in biocompatibility, mechanical compatibility, and long-term patency, with existing materials often leading to thrombosis, inflammatory responses, and intimal hyperplasia due to mismatch in mechanical properties and lack of strength and elasticity.
Innovation Solution
Development of a novel family of biodegradable elastomers, Crosslinked Urethane-containing Polyesters (CUPE), which are used in a scaffold-sheet design with porogen-induced surface roughness and tortuous tunnels to facilitate cell compartmentalization, even distribution, and compliance matching with native tissue, along with the ability to bond physically and provide adequate strength and suture-ability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If natural polymers (collagen, hyaluronic acid, chitosan, fibrin) are used for vascular graft materials, then biocompatibility is improved, but strength and elasticity are insufficient
Solution Approach 1:
The patent uses a composite material system combining natural polymer collagen with synthetic polymer polyglycolic acid (PGA) fibers. The collagen provides biocompatibility and biochemical cues for cell interaction, while the PGA fibers provide mechanical strength and structural support. This composite approach resolves the contradiction by integrating materials with complementary properties.
Solution Approach 2:
The scaffold employs local quality differentiation where the inner surface is coated with collagen to provide biocompatibility and cell adhesion properties, while the structural framework uses PGA fibers for mechanical support. This spatial differentiation of material properties allows each region to fulfill its specific functional requirement.
2Strength
If biodegradable synthetic polymers (PLA, PGA, PCL) are used and rolled into tubes, then mechanical strength is improved, but compliance mismatch and inflammatory responses occur
Solution Approach 1:
The patent combines synthetic PGA fibers for mechanical strength with natural collagen for biocompatibility and compliance matching. The collagen coating on the inner surface provides thromboresistance and endothelial cell adhesion properties, while the PGA framework delivers structural support, resolving the compliance mismatch and inflammatory response issues.
Solution Approach 2:
The scaffold utilizes a porous structure with interconnected pores that allows nutrient diffusion, waste removal, and cell infiltration. The porosity also enables the scaffold to better match the mechanical compliance of native tissue while maintaining structural integrity, addressing both strength and biocompatibility requirements.
3Strength
If scaffold thickness is increased to provide structural support, then mechanical strength is improved, but nutrient delivery and cell distribution at depths greater than 300 μm become insufficient
Solution Approach 1:
The patent employs a highly porous scaffold structure with pore sizes optimized for nutrient diffusion and cell infiltration. The interconnected porous network allows nutrients and oxygen to reach cells throughout the scaffold thickness, eliminating necrotic cores while maintaining structural support through the PGA fiber framework.
Solution Approach 2:
The scaffold transitions from a dense 2D structure to a 3D porous architecture that provides multiple diffusion pathways for nutrients. This dimensional transformation allows nutrient delivery throughout the entire scaffold volume, enabling cell survival and function at depths greater than 300 μm while maintaining structural integrity.
4Reliability
If existing tissue engineered SDBV are implanted, then tissue regeneration is achieved, but long term patency is not attained
Solution Approach 1:
The patent performs preliminary endothelialization of the scaffold before implantation by seeding endothelial cells on the collagen-coated inner surface in vitro. This preliminary action creates a thromboresistant endothelial lining that prevents acute thrombosis and promotes long term patency, addressing the failure mode of existing engineered vessels.
Solution Approach 2:
The scaffold maintains continuous structural support and biochemical cues throughout the tissue regeneration process. The PGA fibers provide sustained mechanical support while collagen continuously presents cell adhesion signals, ensuring uninterrupted tissue maturation and remodeling that leads to long term vessel patency.
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 CUPE scaffolds demonstrate improved biocompatibility, mechanical properties, and long-term patency by allowing cell communication and growth, reducing thrombosis and inflammatory responses, while maintaining structural integrity and facilitating tissue regeneration.
Implementation Method 1
use a porogen to obtain surface roughness and scaffold openings or tunnels
Implementation Method 2
Biodegradable polymers with elastomeric properties have recently received attention for their potential use in the engineering of soft tissues
Implementation Method 3
The scaffold should permit even cell distribution and nutrient delivery at matrix depths greater than 300 μm
Data Source
AI summary
A method of making a new type of biomaterials, biodegrable crosslinked urethane-containing polyester (CUPE) elastomers and a scaffold-sheet engineering method for tissue engineering applications is provided. CUPEs can be synthesized by forming a linear pre-polymer, which is a polyester, introducing the urethane bonds into polyester using a diisocyanate as a linker, and crosslinking the resulting urethane containing linear polymers to form CUPEs via post-polymerization. This family of polymers, CUPEs, exhibit excellent biocompatibility with desired degradation. Tissue engineering scaffolds made of CUPEs are soft and elastic, and have good mechanical strength. Complex tissue grafts can be constructed by a novel layer-by-layer (LBL) scaffold-sheet engineering design using CUPE sheets. CUPE scaffolds can provide openings for cell to cell communication across scaffold layers and angiogenesis into the depth of the construct. Biomolecules, such as anticoagulants, can be incorporated into the CUPE polymers, increasing their viability as vascular graft scaffolds.