Versatile Core-Sheath Biofibers using Coaxial Electrospinning
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1094-DD06-02
Versatile Core-Sheath Biofibers using Coaxial Electrospinning Daewoo Han1, Steven T. Boyce2, and Andrew J. Steckl1 1 Department of Electrical and Computer Engineering, University of Cincinnati, Cincinnati, OH, 45221 2 Department of Surgery, University of Cincinnati, Cincinnati, OH, 45267 ABSTRACT We have investigated coaxial electrospinning to produce core-sheath fibers for tissue engineering. We have successfully produced core-sheath structured fibers of poly(εcaprolactone) (PCL) and gelatin using the coaxial electrospinning technique. The core-sheath scaffold exhibits better mechanical properties compared to gelatin scaffold. We have characterized the resulting core and core-sheath fiber diameters and the scaffold porosity, etc.
INTRODUCTION Electrospinning is a versatile technique for the production of nanofibers of many natural and synthetic materials. This includes biopolymers (DNA1, gelatin2), liquid crystalline polymers (polyaramid)3, textile fiber polymers (nylon)4, electrically conducting polymers (polyaniline)5, etc. Electrospinning uses a high electric field to extract a liquid jet of polymer solution from the liquid reservoir. Sufficient distance between nozzle and substrate is required in order to fully evaporate the solvent. The highly charged liquid jet experiences bending and stretching effects due to charge repulsion and, in the process, becomes continuously thinner. During bending and whipping, the volatile solvent is thoroughly evaporated and the solidified nanofibers are collected on the conducting substrate. Advantages of electrospinning are the ability to control: (a) the fiber diameter from micrometer to nanometer dimensions; (b) the various fiber compositions; (c) the spatial alignment of multiple fibers. Electrospinning can produce nonwoven fiber mats with exceptional surface to volume ratios and with pores which penetrate the entire mat. However, the resulting scaffolds of either natural or synthetic polymers display certain limitations. Natural polymers, such as gelatin and collagen, have very good biocompatibility for cell adhesion and proliferation, but their mechanical strength is not sufficient to support the scaffold during healing process. On the other hand, synthetic polymers, such as PCL, have very good mechanical properties but the therapeutic effectiveness is not as good as that of natural polymers. Therefore, there is a need to develop a novel structure to overcome these limits for tissue engineered scaffolds. The core-sheath structure is an excellent candidate to solve this problem. We have utilized synthetic polymers for the core to take advantage of their mechanical strength and biomaterials for the sheath, such as gelatin, to keep very good biocompatibility of the scaffold. This core-sheath structure enables many possibilities to develop and improve tissue scaffolds for wound healing. To make core-sheath structured fiber, coaxial electrospinning is the most attractive method due to its simplicity and versatility. Coaxial electrospinning was first demonstrated
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