Fabrication of vertically aligned PEDOT nanotube arrays on microelectrodes to interface neurons

To obtain long-term success in chronic implantations, a stable neuron-electrode interface which can seamlessly integrate with brain tissues is required. Compared to conventional flat electrodes, neural electrodes modified with nanostructured materials can provide significantly larger active surface area for charge transfer and neuron-electrode integration. In this study, vertically aligned poly(3,4-ethylenedioxythiophene) (PEDOT) nanotube arrays have been directly fabricated on microelectrodes via a template-mediated technique. It is expected that the PEDOT nanotube arrays could improve the electrical properties of microelectrodes, promote cell adhesion and growth, and increase neurite extension and branching. From our study, ∼2 orders of interfacial impedance decrease and charge capacity density enhancement have been obtained from the PEDOT nanotube array modified microelectrodes. In vitro cellular compatibility tests using PC12 cells showed that PEDOT nanotube arrays supported cell adhesion and growth even without cell adhesion promoted molecules, e.g. collagen and poly-L-lysine (PLL). When treated with nerve growth factor (NGF), larger number of and longer neurites were observed from the cells cultured on PEDOT nanotube arrays compared to those on PLL coated flat substrates.