Integrating Hydrogels to Create Self-Securing Nerve Cuffs

Date

2018-05

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Abstract

Vagus nerve stimulation is an evolving therapy which uses electric stimulators to address various medical conditions and applications. The stimulators utilize nerve cuffs to keep the electrodes secured onto the vagus nerve and require caution during implantation to prevent trauma on nearby tissue. We designed two nerve cuff designs to hold a wireless stimulator and streamline the implantation process by using hydrogels. The cuffs use the swelling of acrylic acidhydroxyethyl acrylate based hydrogels in water to automatically secure the device onto a nerve which reduces overall input needed for implantation. A nerve cuff design using self-folding bilayers strips is able to autonomously bend around a nerve when immersed in water. The bilayers curl reliably and latch around the cuff without manual intervention. With three bilayer strips, the design was able to withstand 33.5 mN of force before failure. The other nerve cuff design uses cylindrical hydrogel pins to secure the cuff closed in place of conventional sutures. Increasing the acrylic acid weight percentage in the hydrogel directly affected the pin’s modulus and the amount of diameter expansion over time. This expansion correlates with the amount of force necessary to pull the cuff apart to failure with larger percentages withstanding greater force upon reaching swelling equilibrium. A pair of 80%AA hydrogel pins could withstand 4.6 N of force after 22 hours of immersion in water. Overall both approaches give the potential of hydrogels in self-securing nerve cuff designs. Hydrogels can reduce the manual input required for implanting the nerve cuff and develop further designs in biomedical devices.

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Colloids in medicine, Vagus nerve, Neural stimulation, Medical electronics

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©2018 The Author. Digital access to this material is made possible by the Eugene McDermott Library. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.

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