Simulations of hydrogel-coated neural microelectrodes to assess biocompatibility improvement using strain as a metric for micromotion

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Bentil, Sarah
Dupaix, Rebecca
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Bentil, Sarah
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Mechanical Engineering
The Department of Mechanical Engineering at Iowa State University is where innovation thrives and the impossible is made possible. This is where your passion for problem-solving and hands-on learning can make a real difference in our world. Whether you’re helping improve the environment, creating safer automobiles, or advancing medical technologies, and athletic performance, the Department of Mechanical Engineering gives you the tools and talent to blaze your own trail to an amazing career.
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The Graduate Program in Neuroscience is an interdepartmental and interdisciplinary training program at Iowa State University that offers the Master of Science and Doctor of Philosophy degrees. The Neuroscience training program offers a broad spectrum of Neuroscience research opportunities, ranging from the molecular to the cellular to the systems level of analysis. The program includes over 40 faculty from the departments of Biochemistry, Biophysics and Molecular Biology; Biomedical Sciences; Chemical and Biological Engineering; Ecology, Evolution, and Organismal Biology; Food Science and Human Nutrition; Genetics, Development and Cell Biology; Kinesiology; Mechanical Engineering; and Psychology.
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Mechanical EngineeringNeuroscience

This study investigates the benefit of coating silicon-substrate microelectrode arrays with hydrogel material for improved biocompatibility. Varying coating thicknesses and hydrogel material descriptions were considered to determine the impact on reducing strain in the surrounding brain tissue caused by relative micromotion of the electrode. Finite element simulations were used to explore biocompatibility by focusing on the longitudinal micromotion of an implanted single electrode shank. The finite element model for the brain and electrode, both with and without the hydrogel coating, remained constant. Three constitutive models were considered to describe the brain and/or hydrogel material: linear elastic, hyperviscoelastic, and fractional Zener. All combinations of these three material descriptions were explored. The simulation results showed that the constitutive model, electrode coating thickness, and the degree of microelectrode adhesion to the brain influenced the maximum principal logarithmic strain and also the maximum electrode displacement. Biocompatibility was improved as evidenced by a reduction in the magnitude of strain in the brain when (i) a hydrogel coating was applied to the silicon electrode, (ii) the thickness of the hydrogel coating was increased, and (iii) the brain adhered completely to the hydrogel coating. A decrease in microelectrode displacement may be a useful metric for assessing an improvement in micromotion reduction.


This is the version of the article before peer review or editing, as submitted by an author to Biomedical Physics & Engineering Express. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it. The Version of Record is available online at DOI: 10.1088/2057-1976/aab990.

Mon Jan 01 00:00:00 UTC 2018