Deciphering platinum dissolution in neural stimulation electrodes: Electrochemistry or biology?

Shah, Dhyey Devashish; Carter, Paul; Shivdasani, Mohit Naresh; Fong, Nicole; Duan, Wenlu; Esrafilzadeh, Dorna; Poole-Warren, Laura Anne; Aregueta Robles, Ulises Alejandro

doi:10.1016/j.biomaterials.2024.122575

Cited by 2 publications

(1 citation statement)

References 188 publications

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“…Tissue samples that were analyzed for trace metals by ICP-MS contained on average of 1.99 ± 3.87 µg of Platinum (0.21 ± 0.41 µg of Iridium). The trace presence of residual Pt and Ir is indicative of dissolution rather than fragmentation given the consideration of the relatively large surface area of the removed microwire structure (~500 mm 2 ) and represents less than 0.02% of the device by weight [29,30]. The helical devices were also visually assessed for the presence of tissue fragments remaining on the device after removal.…”

Section: Tissue Responsementioning

confidence: 99%

Removal Forces of a Helical Microwire Structure Electrode

Howe,

Chen,

Golobish

et al. 2024

Bioengineering

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(1) Background: Medical devices, especially neuromodulation devices, are often explanted for a variety of reasons. The removal process imparts significant forces on these devices, which may result in device fracture and tissue trauma. We hypothesized that a device’s form factor interfacing with tissue is a major driver of the force required to remove a device, and we isolated helical and linear electrode structures as a means to study atraumatic removal. (2) Methods: Ductile linear and helical microwire structure electrodes were fabricated from either Gold (Au) or Platinum–Iridium (Pt-Ir, 90-10). Removal forces were captured from synthetic gel models and following chronic implantation in rodent and porcine models. Devices were fully implanted in the animal models, requiring a small incision (<10 mm) and removal via tissue forceps. (3) Results: Helical devices were shown to result in significantly lower maximal removal forces in both synthetic gel and rodent studies compared to their linear counterparts. Chronically (1 yr.), the maximal removal force of helical devices remained under 7.30 N, for which the Platinum–Iridium device’s tensile failure force was 32.90 ± 2.09 N, resulting in a safety factor of 4.50. (4) Conclusions: An open-core helical structure that can freely elongate was shown to result in reduced removal forces both acutely and chronically.

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Section: Tissue Responsementioning

confidence: 99%