(604c) New Aligned Coaxial Nanofibers for Neural Tissue Engineering

Rachel Martin¹, Michael E. Mullins¹, Feng Zhao², Zichen Qian²

1 Department of Chemical Engineering, Michigan Technological University

2 Department of Biomedical Engineering, Michigan Technological University

Much effort has been recently focused on applying electrospun polymers as scaffolds in many areas of tissue engineering, including skin, bone, cardiovascular and neural tissues. In the case of electrospun fibers for neural tissue applications, some success has been met in vitro. Our group has demonstrated directed axonal outgrowth of dorsal root ganglia (DRG) when cultured on highly aligned electrospun nanofibers made from poly-L-lactic acid (PLLA); yet, less success was achieved during in vivo studies. As an alternative approach for neural applications, we created novel, engineered nanofiber structures via a coaxial electrospinning method. Several coaxial spinning nozzle designs were built and tested with several core/sheath combinations. The objective of this study was to create structures with a conductive polymer core and an insulating PLLA sheath using these coaxial electrospinning. We have designed cell culture studies using these new structures to supply an electric micro-current during in vitro cell studies and to observe the effect on axonal outgrowth. It has been previously shown that electrical stimulation can improve axonal outgrowth in vitro, and that axonal reconnections may be influenced using electrical stimulation. Due to its stable conductive properties, low toxicity, and biocompatibility we have focused on electrospinning poly(3,4-ethylene dioxythiophene) (PEDOT) with polystyrene sulfonate( PSS) as the counter ion to improve solubility. The creation of aligned, coaxial PLLA/PEDOT-PSS nanofibers has been explored, and the resulting fibers characterized via fluorescence microscopy and SEM. The conductive properties of the PLLA/PEDOT-PSS fibers can then be studied using a four-point conductivity test. Once the physical and electrical properties have been confirmed, the aligned fibers are tested during in vitro cell cultures using chick DRG cells. By developing a tissue scaffold stage that can be used with a regular six-well plate, electrical stimulation can be provided along the conductive fibers during in vitro cell cultures. The axonal outgrowth is then measured and compared to cells cultured without electrical stimulation to determine if the axonal outgrowth was improved using electrical stimulation.