Abstract
The mechanical behavior of an electrode during implantation into neural tissue can have a profound effect on the neural connections and signaling that takes place within the tissue. The objective of the present work was to investigate the in vivo implant mechanics of flexible, silicon-based ACREO microelectrode arrays recently developed by the VSAMUEL consortium (European Union, grant #IST-1999-10073). We have previously reported on both the electrical [1]-[3] and mechanical [4], [5] properties of the ACREO electrodes. In this paper, the tensile and compression forces were measured during a series of in vivo electrode insertions into the cerebral cortex of rats (7 acute experiments, 2-mm implant depth, 2-mm/s insertion velocity). We compared the ACREO silicon electrodes (4° opening angle, 1-8 shafts) to single-shaft tungsten electrodes (3° and 10° opening angles). The penetration force and dimpling increased with the cross-sectional area (statistical difference between the largest and the smallest electrode) and with the number of shafts (no statistical difference). We consistently observed tensile (drag) forces during the retraction phase, which indicates the brain tissue sticks to the electrode within a short time period. Treating the electrodes prior to insertion with silane (hydrophobic) or piranha (hydrophilic) significantly decreased the penetration force. In conclusion, our findings suggest that reusable electrodes for acute animal experiments must not only be strong enough to survive a maximal force that exceeded the penetration force, but must also be able to withstand high tension forces during retraction. Careful cleaning is not only important to avoid foreign body response, but can also reduce the stress applied to the electrode while penetrating the brain tissue.
| Original language | English |
|---|---|
| Article number | 1621145 |
| Journal | IEEE Transactions on Biomedical Engineering |
| Volume | 53 |
| Issue number | 5 |
| Pages (from-to) | 934-940 |
| Number of pages | 7 |
| ISSN | 0018-9294 |
| DOIs | |
| Publication status | Published - 01.05.2006 |
Funding
Manuscript received February 3, 2005; revised September 11, 2005. This work was supported in part by the European Union (EU) under Grant IST-1999-10073 and in part by the Danish National Research Foundation. Asterisk indicates corresponding author. *W. Jensen is with Center for Sensory-Motor Interaction, Department of Health Science, Aalborg University, 9220 Aalborg, Denmark (e-mail: [email protected]). Winnie Jensen (S’96–A’00–M’03) received the M.Sc. in electrical engineering in 1997 and the Ph.D. degree in bioengineering in 2001 from the Department of Health Science and Technology, Aalborg University, Aalborg, Denmark. Ken Yoshida (S’89–M’91) received the B.S.E. de-gree in bioengineering in 1989 from the University of California at Los Angeles, and the Ph.D. degree in bioengineering from the University of Utah, Salt Lake City, in 1994. From 1995 to 1998, he was an Alberta Heritage Foundation for Medical Research and a Canadian NeuroScience Network Postdoctoral Fellow with the Division of Neuroscience at the University of Alberta, Edmondton, AB, Canada. He is currently an Associate Professor in the Department of Health Science and Technology at Aalborg, University, Aalborg, Denmark. His research focus is the development of selective neural interfaces, and the application of these devices to study natural neuromuscular control and to investigate natural sensor based FNS systems. Dr. Yoshida is a member of the Society for Neuroscience, the International Functional Electrical Stimulation Society, the Biomedical Engineering Society, the IEEE Engineering in Medicine and Biology Society, and Tau Beta Pi.
