Date of Award

2013

Document Type

Thesis

First Advisor

Bhattarai, Dr. Narayan

Abstract

In the past decade, a wide variety of biomaterials comprised of both synthetic and natural polymers have been used to promote restoration of injured peripheral nerves. Despite making advances, none have matched performance of autographs, a gold standard in nerve repair. Mammalian-derived, protein-based conduits have shown good tissue biocompatibility and safe degradation products, but are mechanically fragile. Synthetic materials such as Polycaprolactone (PCL) typically have advantage of suitable mechanical properties and fine degradation rate tunability, but lack cell recognition signaling. Recent studies have shown that keratin promotes nerve cell attachment, differentiation and growth, but alone, it cannot be used as nerve guide material due to its weak mechanical performances. In the present study we extracted keratin protein from human hair and developed nanofibrous membranes of PCL/ Keratin composites by using electrospinning technique. Morphological analysis of nanofibers was done by scanning electron microscopy (SEM) and physico-chemical properties were analyzed by using X-ray diffraction (XRD), mechanical tensile testing, and Fourier Transform Infrared Spectroscopy (FTIR). Mechanical properties of PCL/Keratin nanofiber membrane showed variation in tensile strength between ratios. Potential use of these nanofibers was studied by examining the integrity in buffer solutions and cellular compatibility. PCL/Keratin fibers confirmed to have non-toxic effects on 3T3 fibroblast cells. SEM imaging showed that PCL/Keratin nanofibers promoted attachment of fibroblast cells and maintained characteristic cell morphology. Thus, appropriately constructed PCL/Keratin based composite nanofibers are expected to demonstrate the favorable biological properties of keratin and the mechanical properties of PCL. These nanofibers are found potential conduit material for peripheral nerve regeneration.

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