Parylene photonics: a flexible, broadband optical waveguide platform with integrated micromirrors for biointerfaces

Reddy, Jay W.; Lassiter, Maya; Chamanzar, Maysamreza

doi:10.1038/s41378-020-00186-2

Cited by 36 publications

(24 citation statements)

References 64 publications

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“…Lastly, it should also be noted that the electrical signals recorded by these systems are prone to stimulation artifacts as a result of photovoltaic effects occurring during the high-intensity illumination of the incorporated recording electrodes [ 126 , 127 ]. However, to reduce this effect, designs including side-emitting waveguides, employing integrated micromirrors [ 128 ] or grating couplers [ 129 ], and shielded recording sites [ 54 ] have been presented.…”

Section: Neural Tissue Illuminationmentioning

confidence: 99%

Technological Challenges in the Development of Optogenetic Closed-Loop Therapy Approaches in Epilepsy and Related Network Disorders of the Brain

et al. 2020

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Epilepsy is a chronic, neurological disorder affecting millions of people every year. The current available pharmacological and surgical treatments are lacking in overall efficacy and cause side-effects like cognitive impairment, depression, tremor, abnormal liver and kidney function. In recent years, the application of optogenetic implants have shown promise to target aberrant neuronal circuits in epilepsy with the advantage of both high spatial and temporal resolution and high cell-specificity, a feature that could tackle both the efficacy and side-effect problems in epilepsy treatment. Optrodes consist of electrodes to record local field potentials and an optical component to modulate neurons via activation of opsin expressed by these neurons. The goal of optogenetics in epilepsy is to interrupt seizure activity in its earliest state, providing a so-called closed-loop therapeutic intervention. The chronic implantation in vivo poses specific demands for the engineering of therapeutic optrodes. Enzymatic degradation and glial encapsulation of implants may compromise long-term recording and sufficient illumination of the opsin-expressing neural tissue. Engineering efforts for optimal optrode design have to be directed towards limitation of the foreign body reaction by reducing the implant’s elastic modulus and overall size, while still providing stable long-term recording and large-area illumination, and guaranteeing successful intracerebral implantation. This paper presents an overview of the challenges and recent advances in the field of electrode design, neural-tissue illumination, and neural-probe implantation, with the goal of identifying a suitable candidate to be incorporated in a therapeutic approach for long-term treatment of epilepsy patients.

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Section: Neural Tissue Illuminationmentioning

confidence: 99%

Technological Challenges in the Development of Optogenetic Closed-Loop Therapy Approaches in Epilepsy and Related Network Disorders of the Brain

et al. 2020

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“…Parylene C has received considerable research attention because of its biocompatibility, chemical inertness, and low moisture permeability, which result in it having suitable barrier properties [24][25][26][27][28]. This material has been used in implantable medical devices, such as implantable nerve recording electrodes [29,30], implantable biomedical chips [31,32], drug delivery systems [32,33], spinal cord stimulators [34,35], and cardiac rhythm devices.…”

Section: Introductionmentioning

confidence: 99%

Wettability and Surface Roughness of Parylene C on Three-Dimensional-Printed Photopolymers

Hsieh

Huang

2022

Materials

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The use of poly-(para-chloro-xylylene) (Parylene C) in microelectromechanical systems and medical devices has increased rapidly. However, little research has been conducted on the wettability and surface roughness of Parylene C after being soaked in solutions. In this study, the contact angle and surface roughness (arithmetic average of roughness) of Parylene C on three-dimensional (3D)-printed photopolymer in 10% sodium hydroxide, 10% ammonium hydroxide, and 100% phosphate-buffered saline (PBS) solutions were investigated using a commercial contact angle measurement system and laser confocal microscope, respectively. The collected data indicated that 10% ammonium hydroxide had no major effect on the contact angle of Parylene C on a substrate, with a Shore A hardness of 50. However, 10% sodium hydroxide, 10% ammonium hydroxide, and 100% PBS considerably affected the contact angle of Parylene C on a substrate with a Shore A hardness of 85. Substrates with Parylene C coating exhibited lower surface roughness than uncoated substrates. The substrates coated with Parylene C that were soaked in 10% ammonium hydroxide exhibited high surface roughness. The aforementioned results indicate that 3D-printed photopolymers coated with Parylene C can offer potential benefits when used in biocompatible devices.

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“…To realize electrical actuation, the MEMS micromirror system consists of two electrodes separated by an isolation layer. The isolation layer mostly comprises silicon dioxide (SiO 2 ), which is the first choice due to its benefits such as providing good insulation between two conducting layers, easy availability, low cost, transparency and high mechanical flexibility [13][14][15][16][17]. The actual fabricated structure of the MEMS-based micromirrors is shown in Figure 3.…”

Section: Introductionmentioning

confidence: 99%

Prediction of Surface Roughness as a Function of Temperature for SiO2 Thin-Film in PECVD Process

et al. 2022

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An analytical model to predict the surface roughness for the plasma-enhanced chemical vapor deposition (PECVD) process over a large range of temperature values is still nonexistent. By using an existing prediction model, the surface roughness can directly be calculated instead of repeating the experimental processes, which can largely save time and resources. This research work focuses on the investigation and analytical modeling of surface roughness of SiO2 deposition using the PECVD process for almost the whole range of operating temperatures, i.e., 80 to 450 °C. The proposed model is based on experimental data of surface roughness against different temperature conditions in the PECVD process measured using atomic force microscopy (AFM). The quality of these SiO2 layers was studied against an isolation layer in a microelectromechanical system (MEMS) for light steering applications. The analytical model employs different mathematical approaches such as linear and cubic regressions over the measured values to develop a prediction model for the whole operating temperature range of the PECVD process. The proposed prediction model is validated by calculating the percent match of the analytical model with experimental data for different temperature ranges, counting the correlations and error bars.

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Parylene photonics: a flexible, broadband optical waveguide platform with integrated micromirrors for biointerfaces

Cited by 36 publications

References 64 publications

Technological Challenges in the Development of Optogenetic Closed-Loop Therapy Approaches in Epilepsy and Related Network Disorders of the Brain

Technological Challenges in the Development of Optogenetic Closed-Loop Therapy Approaches in Epilepsy and Related Network Disorders of the Brain

Wettability and Surface Roughness of Parylene C on Three-Dimensional-Printed Photopolymers

Prediction of Surface Roughness as a Function of Temperature for SiO2 Thin-Film in PECVD Process

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