Preparation and characterization of neural stem cell-loaded conductive hydrogel cochlear implant electrode coatings

Sensorineural deafness is a hearing impairment resulting from damage to the auditory nerve or inner ear hair cells. Currently, cochlear implants (CIs) are widely used as hearing aids for sensorineural deafness patients. A fundamental limitation of cochlear implants (CIs) is that spiral ganglion neurons (SGNs) cannot be replenished. This greatly restricts the rehabilitation of sensorineural deafness. Additionally, the insertion of CIs can cause secondary cochlear damage, worsening the condition of the patients' cochlear. Therefore, a new type of neural stem cells (NSCs) loaded graphene oxide-polyaniline/GelMA (GO-PAni/GelMA) conductive hydrogel electrode for cochlear implant was fabricated via in-situ radical polymerization and cyclic UV curing technique. On the one hand, the hydrogel electrode, as a direct contact layer, helps to avoid the physical hurt for cochlear. On the other hand, NSCs were supplemented via the hydrogel carrier and neuronal differentiation was induced by electrical stimulation, which was validated by the experimental results of immunofluorescence, Phalloidin Staining and RT-qPCR. Furthermore, based on RNA sequencing and transcriptome analysis, we hypothesized that the neuronal differentiation of NSCs was adjusted by the calcium signaling pathway and GABAergic synapse. Overall, our cell loading conductive hydrogel electrode may be an effective solution to sensorineural deafness. The revelation of the mechanism of neuronal differentiation promoted by electrical stimulation provides a basis for further sensorineural deafness treatment using conductive hydrogel CI electrode.