Chronic Stability of Local Field Potentials Using Amorphous Silicon Carbide Microelectrode Arrays Implanted in the Rat Motor Cortex

Jeakle, Eleanor N.; Abbott, Justin; Usoro, Joshua O.; Wu, Yupeng; Haghighi, Pegah; Radhakrishna, Rahul; Sturgill, Brandon S.; Nakajima, Shido; Thai, Teresa Thuc Doan; Pancrazio, Joseph J.; Cogan, Stuart F.; Hernández-Reynoso, Ana G.

doi:10.3390/mi14030680

Cited by 7 publications

(7 citation statements)

References 66 publications

(102 reference statements)

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“…By the seventh day postsurgery, both FLID and SP mice showed increases in their overall activity. However, the activity levels of the FLID mice closely matched those of the Blank mice, with a significant reduction in time spent in the outer area, indicating a return to normal exploratory behavior 44 . Specifically, the FLID group had a travel distance of 54.53 ± 6.51 m, compared to 28.12 ± 11.16 m for the SP group (Fig.…”

Section: Resultsmentioning

confidence: 74%

Through-polymer, via technology-enabled, flexible, lightweight, and integrated devices for implantable neural probes

Zhou,

Tian,

et al. 2024

Microsyst Nanoeng

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In implantable electrophysiological recording systems, the headstage typically comprises neural probes that interface with brain tissue and integrated circuit chips for signal processing. While advancements in MEMS and CMOS technology have significantly improved these components, their interconnection still relies on conventional printed circuit boards and sophisticated adapters. This conventional approach adds considerable weight and volume to the package, especially for high channel count systems. To address this issue, we developed a through-polymer via (TPV) method inspired by the through-silicon via (TSV) technique in advanced three-dimensional packaging. This innovation enables the vertical integration of flexible probes, amplifier chips, and PCBs, realizing a flexible, lightweight, and integrated device (FLID). The total weight of the FLIDis only 25% that of its conventional counterparts relying on adapters, which significantly increased the activity levels of animals wearing the FLIDs to nearly match the levels of control animals without implants. Furthermore, by incorporating a platinum-iridium alloy as the top layer material for electrical contact, the FLID realizes exceptional electrical performance, enabling in vivo measurements of both local field potentials and individual neuron action potentials. These findings showcase the potential of FLIDs in scaling up implantable neural recording systems and mark a significant advancement in the field of neurotechnology.

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Section: Resultsmentioning

confidence: 74%

Through-polymer, via technology-enabled, flexible, lightweight, and integrated devices for implantable neural probes

Zhou,

Tian,

et al. 2024

Microsyst Nanoeng

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“…It can be combined with conductive forms of silicon carbide such as cubic crystalline silicon carbide, which also demonstrates no dissolution at physiological temperatures [35], to create extremely chemically stable devices composed entirely of SiC [166]. a-SiC devices continue to produce good results, recently demonstrating superior in vivo stability compared to a conventional silicon device [167].…”

Section: Emerging Substrate Materials and Architecturesmentioning

confidence: 99%

Lifetime engineering of bioelectronic implants with mechanically reliable thin film encapsulations

Niemiec,

Kim

2023

Prog. Biomed. Eng.

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While the importance of thin form factor and mechanical tissue biocompatibility has been made clear for next generation bioelectronic implants, material systems meeting these criteria still have not demonstrated sufficient long-term durability. This review provides an update on the materials used in modern bioelectronic implants as substrates and protective encapsulations, with a particular focus on flexible and conformable devices. We review how thin film encapsulations are known to fail due to mechanical stresses and environmental surroundings under processing and operating conditions. This information is then reflected in recommending state-of-the-art encapsulation strategies for designing mechanically reliable thin film bioelectronic interfaces. Finally, we assess the methods used to evaluate novel bioelectronic implant devices and the current state of their longevity based on encapsulation and substrate materials. We also provide insights for future testing to engineer long-lived bioelectronic implants more effectively and to make implantable bioelectronics a viable option for chronic diseases in accordance with each patient’s therapeutical timescale.

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“…Substantial efforts to develop new MEA architectures include devices with ultrathin shank dimensions or low modulus of elasticity materials to create flexible devices which aim to mitigate the tissue-device mechanical mismatch. − In addition, administration of pharmacological compounds postimplantation have been investigated including the use of dexamethasone, , resveratrol, dimethyl fumarate, and minocycline . Several groups have recently explored the use of bioactive coatings, with the goal to mitigate neuroinflammation related to decreased chronic recording performance.…”

Section: Introductionmentioning

confidence: 99%

Reactive Amine Functionalized Microelectrode Arrays Provide Short-Term Benefit but Long-Term Detriment to In Vivo Recording Performance

Sturgill,

Hernandez-Reynoso,

Druschel

et al. 2024

ACS Appl. Bio Mater.

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Intracortical microelectrode arrays (MEAs) are used for recording neural signals. However, indwelling devices result in chronic neuroinflammation, which leads to decreased recording performance through degradation of the device and surrounding tissue. Coating the MEAs with bioactive molecules is being explored to mitigate neuroinflammation. Such approaches often require an intermediate functionalization step such as (3aminopropyl)triethoxysilane (APTES), which serves as a linker. However, the standalone effect of this intermediate step has not been previously characterized. Here, we investigated the effect of coating MEAs with APTES by comparing APTES-coated to uncoated controls in vivo and ex vivo. First, we measured water contact angles between silicon uncoated and APTES-coated substrates to verify the hydrophilic characteristics of the APTES coating. Next, we implanted MEAs in the motor cortex (M1) of Sprague−Dawley rats with uncoated or APTES-coated devices. We assessed changes in the electrochemical impedance and neural recording performance over a chronic implantation period of 16 weeks. Additionally, histology and bulk gene expression were analyzed to understand further the reactive tissue changes arising from the coating. Results showed that APTES increased the hydrophilicity of the devices and decreased electrochemical impedance at 1 kHz. APTES coatings proved detrimental to the recording performance, as shown by a constant decay up to 16 weeks postimplantation. Bulk gene analysis showed differential changes in gene expression between groups that were inconclusive with regard to the long-term effect on neuronal tissue. Together, these results suggest that APTES coatings are ultimately detrimental to chronic neural recordings. Furthermore, interpretations of studies using APTES as a functionalization step should consider the potential consequences if the final functionalization step is incomplete.

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Chronic Stability of Local Field Potentials Using Amorphous Silicon Carbide Microelectrode Arrays Implanted in the Rat Motor Cortex

Cited by 7 publications

References 66 publications

Through-polymer, via technology-enabled, flexible, lightweight, and integrated devices for implantable neural probes

Through-polymer, via technology-enabled, flexible, lightweight, and integrated devices for implantable neural probes

Lifetime engineering of bioelectronic implants with mechanically reliable thin film encapsulations

Reactive Amine Functionalized Microelectrode Arrays Provide Short-Term Benefit but Long-Term Detriment to In Vivo Recording Performance

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