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Development and Characterization of a Biohybrid Scaffold for Regenerative Medicine Applications

Freytes, Donald Osvaldo (2008) Development and Characterization of a Biohybrid Scaffold for Regenerative Medicine Applications. Doctoral Dissertation, University of Pittsburgh. (Unpublished)

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Most approaches to tissue engineering and regenerative medicine include a scaffold component. The scaffold material could be synthetic or natural and may be intended simply as a delivery vehicle for cells or growth factors or as an integral component of an engineered tissue or organ. Regardless of the type of material used, the scaffold must be "cell friendly" and promote host cell attachment, proliferation, migration, differentiation, and eventual three-dimensional tissue organization. Biologic scaffolds composed of extracellular matrix have shown minimal scar tissue formation with constructive remodeling of the damaged or missing tissue structures in a variety of clinical and pre-clinical applications. However, ECM scaffolds are typically characterized by a two-dimensional sheet and are limited to the mechanical and material properties inherent to the tissue from which it was derived.A soluble form of ECM scaffold would expand the clinical utility of ECM by allowing the delivery of the scaffold via minimally invasive methods to the site of interest. The present work describes the enzymatic digestion of an ECM scaffold derived from the porcine urinary bladder (urinary bladder matrix or UBM). UBM was successfully digested with pepsin and papain under different conditions. The enzymatically digested UBM showed chemotactic and mitogenic properties towards progenitor cells while inhibition was found toward endothelial cells. In addition, pepsin digested UBM was able to re-polymerize into a gel form. The present study investigated the in vitro cell growth of different cell types on the surface of the gels and measured the rheological properties of the UBM gel.Synthetic scaffold materials are an alternative to naturally derived ECM scaffolds. However, synthetic materials lack the bioactivity and beneficial host tissue response characteristic of ECM-derived scaffolds and often result in fibrous encapsulation when implanted in vivo. Poly(ester-urethane)urea (PEUU) is a biodegradable polymer that can be manufactured into an elastomeric scaffold by electro-spinning techniques with an ultrastructural morphology similar to the ECM. The present work successfully combined the soluble form of the UBM with the PEUU to create hybrid scaffolds. The in vitro characterization of the scaffolds and the in vivo response are described. Hybrid scaffolds showed a change in the host tissue response and higher degradation rates in vivo in a subcutaneous location when compared to the polymer alone. Finally, the potential use of the PEUU and a PEUU/UBM hybrid scaffold as a left ventricular patch in a canine model is discussed.


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Item Type: University of Pittsburgh ETD
Status: Unpublished
CreatorsEmailPitt UsernameORCID
Freytes, Donald
ETD Committee:
TitleMemberEmail AddressPitt UsernameORCID
Committee ChairBadylak, Stephen Fbadylaks@upmc.eduSFB8
Committee MemberVorp, David
Committee MemberWearden, Peter
Committee MemberWagner, William Rwagnerwr@upmc.eduWAGNER
Date: 22 September 2008
Date Type: Completion
Defense Date: 19 March 2008
Approval Date: 22 September 2008
Submission Date: 6 May 2008
Access Restriction: 5 year -- Restrict access to University of Pittsburgh for a period of 5 years.
Institution: University of Pittsburgh
Schools and Programs: Swanson School of Engineering > Bioengineering
Degree: PhD - Doctor of Philosophy
Thesis Type: Doctoral Dissertation
Refereed: Yes
Uncontrolled Keywords: ECM; Scaffolds; Tissue Engineering
Other ID:, etd-05062008-142335
Date Deposited: 10 Nov 2011 19:43
Last Modified: 19 Dec 2016 14:36


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