Fabrication and Characterization of Recombinant Silk-elastinlike Protein Fibers for Tissue Engineering Applications

Persistent Link:
http://hdl.handle.net/10150/201490
Title:
Fabrication and Characterization of Recombinant Silk-elastinlike Protein Fibers for Tissue Engineering Applications
Author:
Qiu, Weiguo
Issue Date:
2011
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
The integration of functional and structural properties makes genetically engineered proteins appealing in tissue engineering. Silk-elastinlike proteins (SELPs), containing tandemly repeated polypeptide sequence derived from natural silk and elastin, are recently under active study due to the interesting structure. The biological, chemical, physical properties of SELPs have been extensively investigated for their possible applications in drug/gene delivery, surgical tissue sealing and spine repair surgery. However, the mechanical aspect has rarely been looked into. Moreover, many other biomaterials have been fabricated into fibers in micrometer and nanometer scale to build extracellular matrix-mimic scaffolds for tissue regeneration, but many have one or mixed defects such as: poor strength, mild toxicity or immune repulsion etc. The SELP fibers, with the intrinsic primary structures, have novel mechanical properties that can make them defects-minimized scaffolds in tissue engineering.In this study, one SELP (SELP-47K) was fabricated into microfibers and nanofibers by the techniques of wet-spinning and electrospinning. Microfibers of meters long were formed and collected from a methanol coagulation bath, and later were crosslinked by glutaraldehyde (GTA) vapor. The resultant microfibers displayed higher tensile strength up to 20 MPa and higher deformability as high as 700% when tested in hydrated state. Electrospinnig of SELP-47K in formic acid and water resulted in rod-like and ribbon-like nanofibrous scaffolds correspondingly. Both chemical (methanol and/or GTA) and physical (autoclaving) crosslinking methods were utilized to stabilize the scaffolds. The chemical crosslinked hydrated scaffolds exhibit elastic moduli of 3.4-13.2 MPa, ultimate tensile strength of 5.7-13.5 MPa, and deformability of 100-130%, closely matching or exceeding the native aortic elastin; while the autoclaved one had lower numbers: 1.0 MPa elastic modulus, 0.3 MPa ultimate strength and 29% deformation. However, the resilience was all above 80%, beyond the aortic elastin, which is 77%. Additionally, Fourier transform infrared spectra showed clear secondary structure transition after crosslinking, explaining the phenomenon of scaffold water-insolubility from structural perspective and showed a direct relationship with the mechanical performance. Furthermore, the in vitro biocompatibility of SELP-47K nanofibrous scaffolds were verified through the culture of NIH 3T3 mouse embryonic fibroblast cells.
Type:
text; Electronic Dissertation
Keywords:
Silk-elastinlike protein; Tissue engineering; Mechanical Engineering; Biomaterial; Scaffold
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Graduate College; Mechanical Engineering
Degree Grantor:
University of Arizona
Advisor:
Wu, Xiaoyi

Full metadata record

DC FieldValue Language
dc.language.isoenen_US
dc.titleFabrication and Characterization of Recombinant Silk-elastinlike Protein Fibers for Tissue Engineering Applicationsen_US
dc.creatorQiu, Weiguoen_US
dc.contributor.authorQiu, Weiguoen_US
dc.date.issued2011-
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractThe integration of functional and structural properties makes genetically engineered proteins appealing in tissue engineering. Silk-elastinlike proteins (SELPs), containing tandemly repeated polypeptide sequence derived from natural silk and elastin, are recently under active study due to the interesting structure. The biological, chemical, physical properties of SELPs have been extensively investigated for their possible applications in drug/gene delivery, surgical tissue sealing and spine repair surgery. However, the mechanical aspect has rarely been looked into. Moreover, many other biomaterials have been fabricated into fibers in micrometer and nanometer scale to build extracellular matrix-mimic scaffolds for tissue regeneration, but many have one or mixed defects such as: poor strength, mild toxicity or immune repulsion etc. The SELP fibers, with the intrinsic primary structures, have novel mechanical properties that can make them defects-minimized scaffolds in tissue engineering.In this study, one SELP (SELP-47K) was fabricated into microfibers and nanofibers by the techniques of wet-spinning and electrospinning. Microfibers of meters long were formed and collected from a methanol coagulation bath, and later were crosslinked by glutaraldehyde (GTA) vapor. The resultant microfibers displayed higher tensile strength up to 20 MPa and higher deformability as high as 700% when tested in hydrated state. Electrospinnig of SELP-47K in formic acid and water resulted in rod-like and ribbon-like nanofibrous scaffolds correspondingly. Both chemical (methanol and/or GTA) and physical (autoclaving) crosslinking methods were utilized to stabilize the scaffolds. The chemical crosslinked hydrated scaffolds exhibit elastic moduli of 3.4-13.2 MPa, ultimate tensile strength of 5.7-13.5 MPa, and deformability of 100-130%, closely matching or exceeding the native aortic elastin; while the autoclaved one had lower numbers: 1.0 MPa elastic modulus, 0.3 MPa ultimate strength and 29% deformation. However, the resilience was all above 80%, beyond the aortic elastin, which is 77%. Additionally, Fourier transform infrared spectra showed clear secondary structure transition after crosslinking, explaining the phenomenon of scaffold water-insolubility from structural perspective and showed a direct relationship with the mechanical performance. Furthermore, the in vitro biocompatibility of SELP-47K nanofibrous scaffolds were verified through the culture of NIH 3T3 mouse embryonic fibroblast cells.en_US
dc.typetexten_US
dc.typeElectronic Dissertationen_US
dc.subjectSilk-elastinlike proteinen_US
dc.subjectTissue engineeringen_US
dc.subjectMechanical Engineeringen_US
dc.subjectBiomaterialen_US
dc.subjectScaffolden_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.disciplineMechanical Engineeringen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorWu, Xiaoyien_US
dc.contributor.committeememberWong, Pak Kinen_US
dc.contributor.committeememberYoon, Jeong-Yeolen_US
dc.contributor.committeememberZohar, Yitshaken_US
dc.contributor.committeememberWu, Xiaoyien_US
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