Development of Electrospun Tissue Engineering Scaffolds with Tunable Properties
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Each year millions of Americans receive grafts to replace and repair damaged tissue such as arteries or skin. Autografts are the current gold standard for treatment; however, synthetic grafts are a common alternative due to the limited availability of autografts. A biodegradable synthetic graft that temporarily replaces the function of the damaged tissue while promoting and directing neotissue formation would combine the availability of synthetic grafts with the healing properties of autografts. To achieve functional repair, the graft needs to have appropriate mechanical properties to restore tissue function and possess the necessary bioactivity to support cell growth and direct stem cell differentiation throughout remodeling. Electrospinning, a technique to fabricate fibrous polymer meshes, has the potential to provide the required control of scaffold properties through alteration of fiber morphology. The high tunability of electrospinning presents a facile method for controlling both mechanical properties and bioactivity of tissue engineering scaffolds; however, an improved understanding of fiber formation and modulation of fiber morphology through varying solution, processing, or environmental parameters is necessary for precise control of scaffold properties. We have developed methods to tune scaffold mechanical properties and bioactivity through modulation of electrospun mesh microarchitecture and in situ gelatin crosslinking. First, we developed methods to improve mesh reproducibility by investigating the effects of environmental and solution parameters on fiber morphology. Segmented polyurethanes (SPUs) were utilized because they possess highly tunable mechanical properties via alteration of segmental chemistry. We have elucidated structure-property relationships of SPUs and the effects of mesh microarchitecture on mechanical properties. This knowledge was used to fabricate a small diameter vascular graft (<4 mm) with mechanical properties similar to native vessels for improved clinical success. Next, we developed in situ crosslinked electrospun gelatin that provides bioactivity for enhanced cell viability and adhesion. This methodology was coupled with a biodegradable SPU into a co-electrospun mesh that combines the robust and tunable mechanical properties of synthetic polymers with the bioactivity of natural polymers. Overall, this work provides methodologies for fabricating electrospun scaffolds with tunable mechanical properties and bioactivity for tissue engineering applications.
in situ crosslinking
Nezarati, Roya M (2014). Development of Electrospun Tissue Engineering Scaffolds with Tunable Properties. Doctoral dissertation, Texas A & M University. Available electronically from