The insulation performance of reactive parylene films in implantable electronic devices

Seymour, John P.; Elkasabi, Yaseen; Chen, Hsien Yeh; Lahann, Joerg; Kipke, Daryl R.

doi:10.1016/j.biomaterials.2009.07.061

Cited by 129 publications

(94 citation statements)

References 33 publications

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“…Davis et al described such moisture diffusion in Parylene-C (Davis et al 2011). Furthermore, water diffusion through parylene leads to an increase in dielectric permittivity and capacitive coupling through the insulation (Seymour et al 2009). In addition, we performed our RAA experiments at temperatures higher than the glass-transition point for Parylene-C (~60 °C).…”

Section: Impact Of the Raamentioning

confidence: 99%

Rapid evaluation of the durability of cortical neural implants using accelerated aging with reactive oxygen species

et al. 2015

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Objective-A challenge for implementing high bandwidth cortical brain-machine interface devices in patients is the limited functional lifespan of implanted recording electrodes. Development of implant technology currently requires extensive non-clinical testing to demonstrate device performance. However, testing the durability of the implants in vivo is timeconsuming and expensive. Validated in vitro methodologies may reduce the need for extensive testing in animal models.Approach-Here we describe an in vitro platform for rapid evaluation of implant stability. We designed a reactive accelerated aging (RAA) protocol that employs elevated temperature and reactive oxygen species (ROS) to create a harsh aging environment. Commercially available microelectrode arrays (MEAs) were placed in a solution of hydrogen peroxide at 87 °C for a period of 7 days. We monitored changes to the implants with scanning electron microscopy and broad spectrum electrochemical impedance spectroscopy (1 Hz-1 MHz) and correlated the physical changes with impedance data to identify markers associated with implant failure.Main results-RAA produced a diverse range of effects on the structural integrity and electrochemical properties of electrodes. Temperature and ROS appeared to have different effects on structural elements, with increased temperature causing insulation loss from the electrode microwires, and ROS concentration correlating with tungsten metal dissolution. All array types experienced impedance declines, consistent with published literature showing chronic (>30 days) declines in array impedance in vivo. Impedance change was greatest at frequencies <10 Hz, and smallest at frequencies 1 kHz and above. Though electrode performance is traditionally characterized by impedance at 1 kHz, our results indicate that an impedance change at 1 kHz is not a reliable predictive marker of implant degradation or failure.Significance-ROS, which are known to be present in vivo, can create structural damage and change electrical properties of MEAs. Broad-spectrum electrical impedance spectroscopy

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Section: Impact Of the Raamentioning

confidence: 99%

Rapid evaluation of the durability of cortical neural implants using accelerated aging with reactive oxygen species

et al. 2015

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“…PC is hydrophobic and is conformably deposited and chemically inert toward most common organic and biological fluids and water till up to 150°C (10). It has a high resistance and elasticity, low dielectric constant, and the highest biocompatibility certification with United States Pharmacopeial Class VI (11,12).…”

Section: Introductionmentioning

confidence: 99%

Histopathological Effects of Parylene C (poly-chloro-p-xylylene) in the Inner Ear

Cevizci

Düzlü

Uyar

et al. 2016

Turk Arch Otorhinolaryngol

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Objective: To assess the histopathological effects of parylene C (PC) (poly-chloro-p-xylylene) in the inner ear. Methods:Nine adult Dunkin Hartley guinea pigs (500-600 g) were included in the study. PC pieces were inserted into the cochlea in the right ear of the animals (study group). The round windows were punctured in the left ears comprised the control group. After three months, the animals were sacrificed, and the dissected temporal bones were examined under a light microscope.Results: No significant difference was revealed between the study and control groups regarding histopathological findings such as perineural congestion, perineural inflammation, neural fibrosis, number of ganglion cells, edema, and degeneration of ganglion cells (p>0.05). Conclusion:PC did not cause any additional histopathologic damage in the cochlea. This finding may be promising regarding the use of PC in cochlear implant electrodes as an alternative to silicon materials in the future.

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“…[27][28][29][30] For our initial investigations of the biocompatibility of our e-skin, we have chosen a relatively simple and safe test, namely The ability to accurately monitor 3D structures, for instance changes of temperature or shape of printed circuit boards, packaged food, or biological organs, without affecting the structure being monitored, presents a unique set of challenges and has been termed imperceptible electronics. [1][2][3][4][5] To achieve such a hefty goal will require developing electronics and materials that are conformal and fl exible.…”

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confidence: 99%

300‐nm Imperceptible, Ultraflexible, and Biocompatible e‐Skin Fit with Tactile Sensors and Organic Transistors

Nawrocki

Matsuhisa

Yokota

et al. 2016

Adv Elect Materials

132

113

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between a human touch, a touch of a metallic object, and no touch, while being immune to noise. Finally, ultralight, at 0.7 g m −2 , it allows for a multitude of applications where the weight of the electronics is of uttermost importance.A fully functioning e-skin, laminated on human subject's hands, is shown in Figure 1 a, with the e-skin device layout depicted in Figure 1 b. It incorporates simple resistive tactile sensors and organic fi eld effect transistors (OFET) used to actively control the sensor information. OFET devices were electrically characterized with recorded average mobility of 0.34 cm 2 Vs −1 , and the ON/OFF ratio of ≈10 5 . Also, the threshold voltage V T , was measured to be approximately −1.72 V. The yield, calculated on 44 devices, was recorded as ≈98%, with only a single faulty device. Following the fabrication process on a rigid glass slide, the devices were manually delaminated and subjected to physical/ mechanical fl exibility tests. The H 2 O-delaminated fi lm was deposited onto a 60% prestretched elastomer that was subsequently relaxed. This resulted in a highly irregular surface, with multiple wrinkles for the fi lm to adhere to. The elastomer was subsequently stretched 100 times to demonstrate good adhesion and physical durability of the devices. The devices were electrically characterized following the physical fl exibility test, with a typical pre-and post-stretched transconductance curves shown in Figure 2 a. It can be seen that the device ON current underwent a marginal increase, with the poststretched average mobility increasing to 0.39 cm 2 Vs −1 , while the OFF and leakage ( I G ) currents, as well as the ON/OFF ratios, remained largely unchanged. The V T also experienced a shift to −1.03 V. Figure 2 b depicts SEM image of an OFET fi lm, placed directly atop of a relaxed elastomer, after the device was electrically characterized. Because the fragile nature of the fi lm did not allow for a direct cross-sectional analysis, angled top view was analyzed instead. The shown image reveals extremely folded and compliant nature of the fi lm. Detailed analysis of the inset reveals a folded edge of the fi lm (top right corner), allowing for extrapolation of a bending radius to being less than 2 µm. This, we believe, is the primary reason why our fi lm can undergo such extreme bending, folding and elastomer stretching, while preserving its good electrical performance.The CVD-deposited biocompatible Parylene serves as the top and bottom (substrate) encapsulation layers, making it an ideal candidate for external and internal medical applications. [27][28][29][30] For our initial investigations of the biocompatibility of our e-skin, we have chosen a relatively simple and safe test, namely The ability to accurately monitor 3D structures, for instance changes of temperature or shape of printed circuit boards, packaged food, or biological organs, without affecting the structure being monitored, presents a unique set of challenges and has been termed imperceptible electronics. [1][2][3][4][5] ...

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The insulation performance of reactive parylene films in implantable electronic devices

Cited by 129 publications

References 33 publications

Rapid evaluation of the durability of cortical neural implants using accelerated aging with reactive oxygen species

Rapid evaluation of the durability of cortical neural implants using accelerated aging with reactive oxygen species

Histopathological Effects of Parylene C (poly-chloro-p-xylylene) in the Inner Ear

300‐nm Imperceptible, Ultraflexible, and Biocompatible e‐Skin Fit with Tactile Sensors and Organic Transistors

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