AVS 49th International Symposium
    Applied Surface Science Friday Sessions
       Session AS+MM+BI-FrM

Invited Paper AS+MM+BI-FrM7
Soft and Fuzzy Polymer Coatings for Microfabricated Neural Prosthetic Devices

Friday, November 8, 2002, 10:20 am, Room C-106

Session: BioMEMS and Medical Devices
Presenter: D.C. Martin, The University of Michigan
Authors: D.C. Martin, The University of Michigan
X. Cui, Unilever
R. Kim, The University of Michigan
J. Yang, The University of Michigan
Y. Xiao, The University of Michigan
Correspondent: Click to Email
Neural prosthetic devices facilitate the functional stimulation of and recording from the peripheral and central nervous systems. It is important that these implantable devices function in vivo for long periods of time. Bioactive and electrically conductive materials are deposited on the surfaces of neural microelectrode arrays through various means to build a stable interface for better biocompatibility and signal transduction. To mediate the mechanical property differences between the brain tissue and silicon device, integrate the device within tissue and minimize the host reaction, bioactive coatings were developed that can be applied over the whole surface of the silicon micro-devices. One approach that has been developed is electrospinning of protein polymers to form a porous film composed of electrospun nano-scale protein fibers with cell-binding sites exposed. Another ongoing approach has been to coat the device with bioactive hydrogel materials which change volume according to their environment, and therefore integrate the device in the tissue with minimal insertion damage. To stabilize the connection between neurons and the electrode sites and facilitate the signal transduction from electrically conductive metal electrode to the ionically conductive tissue, conductive polymers together with bioactive molecules were co-deposited on the electrode site areas by electrochemical deposition. The coatings presented a fuzzy and conductive surface which lowered the impedance of the electrode by 1 to 2 orders of magnitude. The bioactive molecules with cell binding ability in the deposited films on the electrode sites were shown to be able to anchor neurons in both in vitro and in vivo experiments.