Guidance of spiral ganglion neurons over 3 mm using protein patterned surfaces in Co-culture

Abstract

Despite considerable advances in neural prosthetics there are still few clinical devices capable of effectively compensating for the loss of a physiological function. By far the most successful to date are cochlear implants, which can restore the auditory function in patients with severe sensorineural impairment. These implants have electrode arrays that directly stimulate the remaining neurons and several strategies are applied to encourage neurons to interact intimately with the electrodes. Integration of the residual neurons into the circuits can be aided by appropriate micro-patterning on the electrodes’ surfaces to guide the regenerating neurons. Here we describe experiments revealing key features of the interface between auditory cell cultures and surface patterning. In the presented study linear regenerative outgrowth of spiral ganglion axons occurred over distances of several hundred micrometers in the presence of extracellular protein cues placed precisely on surfaces by micro-contact printing. The protein pattern guided the outgrowth of spiral ganglion neurons along interconnected networks of non-neuronal cells. High-precision alignment of axons with no branching or deviation was influenced by, but not dependent upon, the presence of non-glial cells. The findings show that micro-patterning provides a versatile, robust system that can not only guide the outgrowth of individual neurons but also regulate the orientation of diverse cell types in culture.