Functionalized Coatings for Enhanced Neural Interfaces

DESCRIPTION (provided by applicant): The development of a biologically active coating for electrodes used in recording and stimulation of the nervous system is proposed. The coating is based on a co-polymer of poly(ethylene glycol)/polylactic acid (PEG-PLA) that contains a neurotrophic factor as a slowly releasable constituent. Release of the neurotrophin promotes the extension of neural processes to the electrode surface. The close proximity of the electrode to viable neural processes will enhance the stability and sensitivity of neural recordings and may reduce charge- injection thresholds for neural excitation. Surface treatment of electrodes with cell adhesion peptides will also be evaluated as a means of preserving the interface once the neurotrophic factor is exhausted. Our objectives for the Phase II effort are 1) to assess the benefits of neurotrophin-eluting polymers on microelectrodes implanted in an animal model appropriate to intracortical recording for direct thought-based control of extracorporal devices for the spinal cord injured, 2) to assess the benefit of neurotrophin-eluting coatings on stimulation electrodes in a model of neurodegenerative disease, specifically retinal stimulation electrodes in visual prostheses for retinitis pigmentosa, and 3) to evaluate the use of surface-bound coatings of peptide adhesion molecules to chronically stabilize the close proximity of neural processes at the electrode surface established by short-term neurotrophin elution. Prostheses are being developed for individuals with spinal cord injury, deafness, blindness and diseases that impair movement. These prostheses will function by electrically stimulating nerves or by recording nerve activity in the brain. The use of biodegradable coatings on these electrodes to enhance the electrical connection between the implanted metal electrodes and nerve cells in the brain is proposed. The coatings will elute biologically active molecules that encourage nerve cells to grow to the implanted electrodes, increasing the efficiency and reliability of the stimulation and recording properties of the prostheses.