Chronic Softening Spinal Cord Stimulation Arrays

dc.contributor.ORCID0000-0003-0135-0531 (Voit, WE)
dc.contributor.authorGarcia-Sandoval, Aldo
dc.contributor.authorPal, A.
dc.contributor.authorMishra, A. M.
dc.contributor.authorSherman, Sydney
dc.contributor.authorParikh, Ankit R.
dc.contributor.authorJoshi-Imre, Alexandria
dc.contributor.authorArreaga-Salas, David
dc.contributor.authorGutierrez-Heredia, Gerardo
dc.contributor.authorDuran-Martinez, Adriana C.
dc.contributor.authorNathan, J.
dc.contributor.authorHosseini, Seyed Mahmoud
dc.contributor.authorCarmel, J. B.
dc.contributor.authorVoit, Walter E.
dc.contributor.utdAuthorGarcia-Sandoval, Aldo
dc.contributor.utdAuthorSherman, Sydney
dc.contributor.utdAuthorParikh, Ankit R.
dc.contributor.utdAuthorJoshi-Imre, Alexandria
dc.contributor.utdAuthorArreaga-Salas, David
dc.contributor.utdAuthorGutierrez-Heredia, Gerardo
dc.contributor.utdAuthorDuran-Martinez, Adriana C.
dc.contributor.utdAuthorHosseini, Seyed Mahmoud
dc.contributor.utdAuthorVoit, Walter E.
dc.descriptionIncludes supplementary material
dc.descriptionFull text access from Treasures at UT Dallas is restricted to current UTD affiliates.
dc.description.abstractObjective. We sought to develop a cervical spinal cord stimulator for the rat that is durable, stable, and does not perturb the underlying spinal cord. Approach. We created a softening spinal cord stimulation (SCS) array made from shape memory polymer (SMP)-based flexible electronics. We developed a new photolithographic process to pattern high surface area titanium nitride (TiN) electrodes onto gold (Au) interconnects. The thiol-ene acrylate polymers are stiff at room temperature and soften following implantation into the body. Durability was measured by the duration the devices produced effective stimulation and by accelerated aging in vitro. Stability was measured by the threshold to provoke an electromyogram (EMG) muscle response and by measuring impedance using electrochemical impedance spectroscopy (EIS). In addition, spinal cord modulation of motor cortex potentials was measured. The spinal column and implanted arrays were imaged with MRI ex vivo, and histology for astrogliosis and immune reaction was performed. Main results. For durability, the design of the arrays was modified over three generations to create an array that demonstrated activity up to 29 weeks. SCS arrays showed no significant degradation over a simulated 29 week period of accelerated aging. For stability, the threshold for provoking an EMG rose in the first few weeks and then remained stable out to 16 weeks; the impedance showed a similar rise early with stability thereafter. Spinal cord stimulation strongly enhanced motor cortex potentials throughout. Upon explantation, device performance returned to pre-implant levels, indicating that biotic rather than abiotic processes were the cause of changing metrics. MRI and histology showed that softening SCS produced less tissue deformation than Parylene-C arrays. There was no significant astrogliosis or immune reaction to either type of array. Significance. Softening SCS arrays meet the needs for research-grade devices in rats and could be developed into human devices in the future.
dc.description.departmentErik Jonsson School of Engineering and Computer Science
dc.description.sponsorshipNIH R21EB020318 grant
dc.identifier.bibliographicCitationGarcia-Sandoval, A., A. Pal, A. M. Mishra, S. Sherman, et al. 2018. "Chronic softening spinal cord stimulation arrays." Journal of Neural Engineering 15(4): art. 045002, doi:10.1088/1741-2552/aab90d
dc.publisherInstitute of Physics Publishing
dc.rights©2018 IOP Publishing Ltd.
dc.source.journalJournal of Neural Engineering
dc.subjectBrain-computer interfaces
dc.subjectShape memory polymers
dc.subjectTitanium nitride
dc.subjectImpedance spectroscopy
dc.subjectFlexible electronics
dc.subjectGold compounds
dc.subjectShape memory effect
dc.titleChronic Softening Spinal Cord Stimulation Arrays


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