Long-term stability of intracortical recordings using perforated and arrayed Parylene sheath electrodes

Hara, Seth A.; Kim, Brian J.; Kuo, Jen-Tsai; Lee, Curtis D.; Meng, Ellis; Pikov, Victor

doi:10.1088/1741-2560/13/6/066020

Cited by 45 publications

(34 citation statements)

References 62 publications

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“…Thin parylene films are desirable packaging materials because they are hydrophobic barrier layers, present limited intrinsic biological activity, offer robust dielectric properties, and preserve mechanical flexibility (Loeb et al, 1977). Despite the relatively large hydraulic permeability of parylene compared to many inorganic films, flexible neural probes encapsulated in parylene-C achieve stable in vivo recordings for 12 months or longer (Hara et al, 2016). Nanoscale diamond is another emerging class of packaging materials (Narayan et al, 2011).…”

Section: Trends In Materials For Flexible Barrier Layersmentioning

confidence: 99%

Recent advances in materials and flexible electronics for peripheral nerve interfaces

Bettinger

2018

Bioelectron Med

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Peripheral nerve interfaces are a central technology in advancing bioelectronic medicines because these medical devices can record and modulate the activity of nerves that innervate visceral organs. Peripheral nerve interfaces that use electrical signals for recording or stimulation have advanced our collective understanding of the peripheral nervous system. Furthermore, devices such as cuff electrodes and multielectrode arrays of various form factors have been implanted in the peripheral nervous system of humans in several therapeutic contexts. Substantive advances have been made using devices composed of off-the-shelf commodity materials. However, there is also a demand for improved device performance including extended chronic reliability, enhanced biocompatibility, and increased bandwidth for recording and stimulation. These aspirational goals manifest as much needed improvements in device performance including: increasing mechanical compliance (reducing Young's modulus and increasing extensibility); improving the barrier properties of encapsulation materials; reducing impedance and increasing the charge injection capacity of electrode materials; and increasing the spatial resolution of multielectrode arrays. These proposed improvements require new materials and novel microfabrication strategies. This mini-review highlights selected recent advances in flexible electronics for peripheral nerve interfaces. The foci of this mini-review include novel materials for flexible and stretchable substrates, non-conventional microfabrication techniques, strategies for improved device packaging, and materials to improve signal transduction across the tissue-electrode interface. Taken together, this article highlights challenges and opportunities in materials science and processing to improve the performance of peripheral nerve interfaces and advance bioelectronic medicine.

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Section: Trends In Materials For Flexible Barrier Layersmentioning

confidence: 99%

Recent advances in materials and flexible electronics for peripheral nerve interfaces

Bettinger

2018

Bioelectron Med

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“…For example, an autoclave creates a high temperature and high humidity environment for sterilization, which can cause Parylene bilayers to delaminate and Parylene coatings to lose adhesion [ 57 , 91 ]. Alternative methods, such as the use of ethylene oxide, have been used successfully without damage to thin-film Parylene devices [ 36 ]. Several methods for sterilizing Parylene devices are described in literature and a brief summary of various methods and the major conclusions drawn regarding the effect on Parylene, is compiled in Table 2 .…”

Section: Challengesmentioning

confidence: 99%

“…Other devices include neurocages for in vitro neural network study [ 26 , 27 , 28 ], bellows for drug delivery [ 29 , 30 , 31 ], an electrochemical patency sensor [ 32 ], microfluidic devices [ 7 ] and electrothermal valves [ 33 ]. In the field of neural prostheses Parylene was used to create both penetrating ( Figure 3 c) [ 34 , 35 , 36 , 37 , 38 , 39 ] and non-penetrating microelectrode arrays [ 40 , 41 , 42 ]. Microfluidic channels were integrated into Parylene neural probes to inject drugs [ 43 , 44 , 45 ].…”

Section: Introductionmentioning

confidence: 99%

Techniques and Considerations in the Microfabrication of Parylene C Microelectromechanical Systems

et al. 2018

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Parylene C is a promising material for constructing flexible, biocompatible and corrosion-resistant microelectromechanical systems (MEMS) devices. Historically, Parylene C has been employed as an encapsulation material for medical implants, such as stents and pacemakers, due to its strong barrier properties and biocompatibility. In the past few decades, the adaptation of planar microfabrication processes to thin film Parylene C has encouraged its use as an insulator, structural and substrate material for MEMS and other microelectronic devices. However, Parylene C presents unique challenges during microfabrication and during use with liquids, especially for flexible, thin film electronic devices. In particular, the flexibility and low thermal budget of Parylene C require modification of the fabrication techniques inherited from silicon MEMS, and poor adhesion at Parylene-Parylene and Parylene-metal interfaces causes device failure under prolonged use in wet environments. Here, we discuss in detail the promises and challenges inherent to Parylene C and present our experience in developing thin-film Parylene MEMS devices.

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“…In the case of soft polymer-based devices, while the former has been the subject of numerous studies [11,12,13,3], the latter remains little known. The mechanisms leading to changes in the properties of biomedical polymers are considered part of biodegradation mechanisms aecting its longevity.…”

Section: Introductionmentioning

confidence: 99%

“…Some involve short-term implantation, between 3 weeks [19] and 5 weeks [20,21]. Recently, studies by Ellis Meng and coworkers showed proof of electrical recordings in rats for a period of 3 to 12 months, and primary investigation was carried out over signal quality [11], as well as immunohistochemical analysis [12]. But overall, if Parylene C is largely being investigated as a substrate for chronically-implanted neural probes, the stability of Parylene-based devices lacks crucial perspective.…”

Section: Introductionmentioning

confidence: 99%

In vitro and in vivo biostability assessment of chronically-implanted Parylene C neural sensors

Lecomte

Degache

Descamps

et al. 2017

Sensors and Actuators B: Chemical

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Parylene C has rapidly gained attention as a exible biomaterial for a new generation of chronic neural probes. However, polymeric material failure in the form of delamination, swelling or tearing, often compromises device biostability in the long term. This work constitutes a rst step towards lifetime assessment of Parylene C implanted devices. We have conceived a Parylene C-based neural probe with PEDOT-nanostructured gold electrodes for the recording of brain activity. The material response to its biological environment was studied through in vitro soaking tests and in vivo wireless recordings in mice brain, both carried out for up to 6 months. Impedance monitoring and SEM images indicate that over the length of this trial, none of the implants presented with apparent signs of material degradation.Packaging reliability was a predominant factor in device failure, with a certain number of faulty connection appearing over time. This parameter aside, all soaked devices were stable in Articial Cerebro-Spinal Fluid, with impedances within 10% of their initial value after 6 months at 37°C. Besides, at least 70% of the implanted device were able to accurately record wirelessly high amplitude hippocampal Local Field Potentials from freely-moving mice, with steady Signal-to-Noise Ratio. In other terms, Parylene C implantable sensors responded minimally to articial and actual physiological conditions during a period of 6 months, which makes them promising candidates for reliable, chronically implanted sensors in the biomedical eld.

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Long-term stability of intracortical recordings using perforated and arrayed Parylene sheath electrodes

Cited by 45 publications

References 62 publications

Recent advances in materials and flexible electronics for peripheral nerve interfaces

Recent advances in materials and flexible electronics for peripheral nerve interfaces

Techniques and Considerations in the Microfabrication of Parylene C Microelectromechanical Systems

In vitro and in vivo biostability assessment of chronically-implanted Parylene C neural sensors

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