Near-field electrospun vascular scaffolds with controlled pore size
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Solution Overview
Problem
Current electrospinning techniques for creating fibrous scaffolds face limitations in tailoring fiber diameters and pore sizes, which restrict the range of scaffold architectures that can facilitate angiogenesis and cellular ingrowth, particularly for small-diameter vascular grafts, leading to high failure rates due to thrombosis and mechanical property mismatch.
Innovation Solution
The development of near-field electrospinning (NFES) techniques that allow for precise control over fiber placement and architecture by shortening the air gap and using a counter electrode with precise relative motion, enabling the creation of hybrid fibrous scaffolds with tailored fiber diameters, pore sizes, and mechanical properties independent of each other, including the use of polydioxanone (PDO) scaffolds with aligned grid structures and random infill for vascular grafts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional electrospinning (TES) is used to create fibrous scaffolds, then highly porous structures are achieved, but fiber diameter and pore size are intrinsically related so that adjusting one affects the other, severely limiting the range of fiber diameters
Solution Approach 1:
The patent segments the fiber deposition process into controlled stages using multiple electrodes arranged in arrays. By independently controlling the voltage and positioning of each electrode, the system can deposit fibers with precise diameter control while maintaining versatility in the range of achievable diameters, resolving the intrinsic coupling limitation of TES
Solution Approach 2:
The patent changes multiple parameters simultaneously including electrode spacing, voltage amplitude, frequency, and duty cycle to independently control fiber diameter and pore size. This multi-parameter control approach decouples the relationship between fiber diameter and pore size that exists in traditional electrospinning
2Manufacturing precision
If near-field electrospinning (NFES) is used to shorten the air gap and enable precise fiber placement, then fiber architecture control is improved, but the resulting scaffolds consist of straight-line fibers that lack random fibrous qualities necessary for promoting cellular growth
Solution Approach 1:
The patent introduces dynamic control by varying the voltage, frequency, and positioning of electrodes during the deposition process. This dynamic adjustment allows the system to switch between ordered straight-line fiber patterns and more random fibrous configurations, enabling both precise placement and cellular growth promotion
Solution Approach 2:
The patent employs periodic voltage application with variable duty cycles to control fiber deposition patterns. By modulating the electrical parameters periodically, the system can create alternating regions of ordered and random fiber structures within the same scaffold, combining precision placement with cellular growth benefits
3Length of moving object
If small-diameter grafts are created using current techniques, then the graft size is reduced for better fit, but failure rates increase due to thrombosis and mechanical property mismatch
Solution Approach 1:
The patent applies local quality by creating regions with different fiber diameters, orientations, and densities within the graft structure. The inner layer can have smaller, more densely packed fibers to match the small graft diameter and prevent thrombosis, while outer layers have larger, more random fibers to provide mechanical strength and promote tissue integration
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
NFES enables the production of scaffolds with larger pore sizes and improved mechanical properties, facilitating transmural capillary ingrowth and reducing platelet adhesion, thus addressing the limitations of traditional electrospun scaffolds and commercial grafts like GORE-TEX, potentially leading to more effective vascular grafts with enhanced biocompatibility and durability.
Implementation Method 1
A high-voltage power supply is connected to the capillary and a counter electrode or ground
Implementation Method 2
writing the polymer-containing solution on a counter electrode to form semi-stable fibers comprised of the polymer
Data Source
AI summary
Methods of producing hybrid fibrous scaffolds are provided. The methods include dissolving a polymer, such as polydioxanone, in a solution, such as 1,1,1,3,3,3-hexafluoro-2-propanol (HFP), to form a polymer-containing solution. The method comprises electrically charging the polymer-containing solution. The method comprises writing the polymer-containing solution on a counter electrode or a ground in a grid pattern to form semi-stable fibers comprised of the polymer, the semi-stable fibers vary between bent and straight and forming the hybrid fibrous scaffold. The writing may be performed by a 3D printer. The resulting scaffolds and methods of using the same are also disclosed herein.