Aligned and electrospun piezoelectric polymer fiber assembly and scaffold
Inventors
Scott Carnell, Lisa A. • Siochi, Emilie J. • Holloway, Nancy M. • Leong, Kam W. • Kulangara, Karina
Assignees
National Aeronautics and Space Administration NASA
Publication Number
US-9758761-B2
Publication Date
2017-09-12
Expiration Date
2030-12-15
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Abstract
A method of manufacturing and/or using a scaffold assembly for stem cell culture and tissue engineering applications is disclosed. The scaffold at least partially mimics a native biological environment by providing biochemical, topographical, mechanical and electrical cues by using an electroactive material. The assembly includes at least one layer of substantially aligned, electrospun polymer fiber having an operative connection for individual voltage application. A method of cell tissue engineering and/or stem cell differentiation that uses the assembly seeded with a sample of cells suspended in cell culture media, incubates and applies voltage to one or more layers, and thus produces cells and/or a tissue construct. In another aspect, the invention provides a method of manufacturing the assembly including the steps of providing a first pre-electroded substrate surface; electrospinning a first substantially aligned polymer fiber layer onto the first surface; providing a second pre-electroded substrate surface; electrospinning a second substantially aligned polymer fiber layer onto the second surface; and, retaining together the layered surfaces with a clamp and/or an adhesive compound.
Core Innovation
The invention disclosed provides a scaffold assembly and related methods for stem cell culture and tissue engineering applications that at least partially mimic a native biological environment. It achieves this by providing biochemical, topographical, mechanical, and electrical cues using an electroactive material. The scaffold assembly includes at least one layer of substantially aligned, electrospun polymer fiber with an operative connection for individual voltage application to deliver electrical stimuli.
The invention also addresses the method of manufacturing the assembly by providing electroded substrate surfaces onto which layers of electrospun, substantially aligned polymer fibers are deposited. These layered surfaces are then retained together using a clamp and/or adhesive compound. Additionally, the method of cell tissue engineering and/or stem cell differentiation using the assembly includes seeding the scaffold with a sample of cells suspended in culture media, incubating, applying an effective voltage to one or more layers, and recovering cells or tissue constructs.
The problem being solved arises from the background that current scaffold designs and materials do not provide all the appropriate cues necessary to mimic in vivo conditions for tissue engineering and stem cell engineering. Particularly, while biochemical and mechanical stimuli have been incorporated in typical cell seeding environments, electrical cues have only recently been considered. Therefore, there is a need for novel scaffolds that can provide electrical stimuli in conjunction with biochemical and mechanical cues to significantly impact stem cell proliferation, differentiation, and tissue construct engineering.
Claims Coverage
The patent contains one independent claim which covers the method of manufacturing an assembly for tissue engineering and/or stem cell differentiation with specific structural and functional features.
Method of manufacturing a multi-layer scaffold assembly
Provides steps of preparing a first substrate surface with a first electrode, electrospinning a first substantially aligned polymer fiber layer onto it, independently preparing one or more additional substrate surfaces each with electrodes, electrospinning aligned polymer fiber layers onto these additional surfaces, and then retaining the layers together with a clamp to provide a suspended scaffold for cell growth between electrodes. The configuration ensures that electrical or mechanical stimulation to one layer does not stimulate another layer.
Preparation of substrate surface electrodes by evaporation
Substrate electrodes are prepared by fabricating the substrate from a polymer sheet and evaporating metal, such as gold, onto the substrate to form the electrodes.
Use of auxiliary electrode in electrospinning to align fibers
The electrospinning steps use an auxiliary electrode to create a dipole field that focuses the electric field to generate substantially aligned electrospun polymer fibers.
Use of electroactive polymer fibers including PVDF
The polymer fibers electrospun are electroactive polymers. Specifically, polyvinylidene fluoride (PVDF) is used as the electroactive polymer to impart electrical and mechanical stimulus capabilities to the scaffold.
These inventive features collectively provide a method to manufacture a multi-layer scaffold assembly with individually electrically addressable, substantially aligned electrospun polymer fiber layers retained by a clamp to enable electrical and mechanical stimulation for tissue engineering and stem cell differentiation.
Stated Advantages
The scaffold assembly provides biochemical, topographical, mechanical, and electrical cues that more closely mimic native biological environments.
Electrical stimuli can be delivered through bioactive fibers which significantly impact the proliferation and differentiation of stem cells and engineered tissue constructs.
The scaffold allows individual voltage application to multiple layers, enabling controlled and independent stimulation.
The use of electroactive polymers such as PVDF ensures in situ poling and electroactive properties without post-processing.
The scaffold supports a three-dimensional architecture that promotes cell attachment, proliferation, and aligned growth, improving the in vitro environment for stem cell culture.
Documented Applications
Stem cell therapy treatment methods for spinal cord disorders, autoimmune diseases, and Parkinson's disease.
Tissue engineering constructs for myocardial infarcts, blood vessels, and skin grafts.
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