Monika Seegers (Hannover, DE), Dr. Jennifer Harre (Hannover, DE), Dr. Madeleine Goblet (Hannover, DE), Dr. Nina Ehlert (Hannover, DE), Professor Thomas Lenarz (Hannover, DE), Professor Athanasia Warnecke (Hannover, DE), Prof. Dr. Peter Behrens (Hannover, DE)
Abstract text (incl. figure legends and references)
In case of sensorineural hearing loss, a cochlear implant can be implanted to help the patient to hear again. But the problem with this is, that the distance between the implant"s electrode and the spiral ganglion neurons (SGN) is rather large. As a result, there is a loss in signal transmission and poor auditory perception. To solve this problem, an enhanced electrode-nerve contact is needed.
A neuronal guidance scaffold based on polymer fibres attached to the cochlear implant is designed to accomplish this. To mimic the extracellular matrix (ECM), heparan sulphate (HS) and laminin are covalently attached to these fibres. Then the growth factors brain-derived neurotrophic factor (BDNF) and neurotrophin-3 (NT-3) are added. The growth factors are anticipated to be released and ought to benefit the SGN"s survival and neurite outgrowth. The ECM components should encourage the neurites to grow along the fibres once they are in contact with them with the final goal to increase the electrode-nerve contact.
First, an aminolysis was performed with the fibres to get amino groups on the surface. Then, HS was covalently attached to unmodified and amino-modified fibres. Following that, the fibres were incubated in a BDNF/NT-3 solution and release experiments were done to evaluate the release behaviours. In addition, cell culture studies with supernatants were carried out to determine the effect of the released growth factor on SGN. In another experiment, laminin was covalently bound to the fibres and SGN explants were put on them.
The fibres were successfully modified with amino-groups on the surface. In the release experiments it was shown, that the release of growth factors is more continuous from the amino-modified fibres. And there is an effect on the survival rate of SGN. In the studies with laminin it was shown that explants with SGN can grow on the coated fibres.
The fibres show promising results with regard to their use as a neuronal guidance scaffold for SGN neurites.