Design and fabrication of neural implant with thick microchannels based on flexible polymeric materials

Mechanical guidance can be used to provide a supporting structure through which and onto which regenerating axons can grow. The dimensions of the mechanical guide need to be suitable to support regenerated axon outgrowth and vascularisation. In this paper, we present the design and fabrication process of a three-dimensional (3D) device comprising a bundle of parallel (100 microm x 100 microm) microchannels with embedded electrodes. This device can be used as a 3D electrode interface for peripheral nerve repair. The skeleton of the device is entirely made of flexible polyimide films. Gold microelectrodes and microchannels of photosensitive polyimide are patterned directly on polyimide substrates. After fabrication, the 2D electrode channel array is rolled into a 3D channel bundle that fits the anatomy of the peripheral nerve. Samples are rolled and inserted into 1.5mm inner diameter tube.