A PDMS microchannel scaffold with microtube electrodes for peripheral Nerve Interfacing

Neural interface devices have been used to retrieve bioelectrical signals from the nervous system to control prosthetics and muscle stimulators. The ability to identify specific electrical signals is important in order to control prosthetics and muscle stimulators. In this paper, we present the Texas peripheral Nerve Interface (TxNI) which combines a PDMS microchannel scaffold with microelectrodes and is designed to retrieve detailed electrical signals (electroneurogram) from the peripheral nervous system. The microchannel is microfabricated using PDMS and commercially available wires. The diameter of scaffold is approximately 2 mm, and the fabricated length of the scaffold can be 10cm or longer. The number of the microchannels, and the diameter of each channel, can be controlled by using different sizes of wire. For the first generation TxNI, commercially available micro wires were used to implement the device efficiently. The second generation TxNI has been further developed, which replaces microwires with gold microtube electrodes. The first generation TxNI has been successfully implanted inside small animals and the bioelectrical signals were captured from the regenerated nerves. The gold microtube electrode of the second generation TxNI was microfabricated using commercially available copper wires and gold electroplating solution. The diameter of gold microtube electrodes can be controlled by using different sizes of wires during the electroplating process; thickness is determined by the duration of the electroplating process. We implemented the gold microtube electrode into individual microchannels so as to retrieve the bioelectric signal from regenerated nerves inside gold microtube electrodes.