Insertion of Flexible Neural Probes Using Rigid Stiffeners Attached with Biodissolvable Adhesive |
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Authors: | Sarah H. Felix Kedar G. Shah Vanessa M. Tolosa Heeral J. Sheth Angela C. Tooker Terri L. Delima Shantanu P. Jadhav Loren M. Frank Satinderpall S. Pannu |
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Affiliation: | 1.Materials Engineering Division, Lawrence Livermore National Laboratory;2.UCSF Center for Integrative Neuroscience and the Department of Physiology, University of California, San Francisco |
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Abstract: | Microelectrode arrays for neural interface devices that are made of biocompatible thin-film polymer are expected to have extended functional lifetime because the flexible material may minimize adverse tissue response caused by micromotion. However, their flexibility prevents them from being accurately inserted into neural tissue. This article demonstrates a method to temporarily attach a flexible microelectrode probe to a rigid stiffener using biodissolvable polyethylene glycol (PEG) to facilitate precise, surgical insertion of the probe. A unique stiffener design allows for uniform distribution of the PEG adhesive along the length of the probe. Flip-chip bonding, a common tool used in microelectronics packaging, enables accurate and repeatable alignment and attachment of the probe to the stiffener. The probe and stiffener are surgically implanted together, then the PEG is allowed to dissolve so that the stiffener can be extracted leaving the probe in place. Finally, an in vitro test method is used to evaluate stiffener extraction in an agarose gel model of brain tissue. This approach to implantation has proven particularly advantageous for longer flexible probes (>3 mm). It also provides a feasible method to implant dual-sided flexible probes. To date, the technique has been used to obtain various in vivo recording data from the rat cortex. |
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Keywords: | Bioengineering Issue 79 Nervous System Diseases Surgical Procedures Operative Investigative Techniques Nonmetallic Materials Engineering (General) neural interfaces polymer neural probes surgical insertion polyethylene glycol microelectrode arrays chronic implantation |
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