Active Research

Principal Investigators: Allen Ryan, PhD

Objective: To explore bioengineering strategies for the rehabilitation of hearing loss using a hybrid biological and electrical prosthesis. This study aims to improve the cochlear implant by combining device engineering and biological approaches. More specifically, cochlear implant performance will be enhanced by decreasing the distance between the implant electrodes and the cochlear neurons, so that more channels of information can be delivered, and also by increasing the survival of cochlear neurons. This research may improve cochlear prostheses and provide a model for developing biological interfaces to improve neural connections to other types of electrical stimulating devices.

Background: These devices are widely used to treat the deaf, and now are increasingly used for patients with small amounts of residual hearing. However, while they provide substantial benefit to profoundly deaf individuals, they by no means restore hearing to normal.

Findings: The response profiles of adult spiral ganglion neurons to neurotrophins, including neurotrophin-3 and brain-derived neurotrophic factor have been established. In addition, the requirement of neurites for a co-receptor in order to achieve maximal responses with glial-derived neurotrophic factor has been determined. Procedures for engineering growth substrate patterns so that neurites can be channeled along preferred paths, and procedures for testing directional guidance induced by soluble factors have been developed, along with development of three-dimensional matrixes that support neurite growth through fluid spaces.