Techniques and Considerations in the Microfabrication of Parylene C Microelectromechanical Systems

Ortigoza-Diaz, Jessica; Scholten, Kee; Larson, Christopher; Cobo, Angelica; Hudson, Trevor; Yoo, Jennie; Baldwin, Alex; Hirschberg, Ahuva Weltman; Meng, Ellis

doi:10.3390/mi9090422

Cited by 112 publications

(88 citation statements)

References 109 publications

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“…As reported in literature, parylene, similar to all polymers, is permeable to moisture [2]- [8]. The weak adhesion of parylene to Pt, therefore, would allow water condensation on the Pt tracks.…”

Section: Discussionmentioning

confidence: 68%

Effect of Signals on the Encapsulation Performance of Parylene Coated Platinum Tracks for Active Medical Implants

Nanbakhsh

Kluba

Pahl

et al. 2019

2019 41st Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC)

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Platinum is widely used as the electrode material for implantable devices. Owing to its high biostability and corrosion resistivity, platinum could also be used as the main metallization for tracks in active implants. Towards this goal, in this work we investigate the stability of parylene-coated Pt tracks using passive and active tests. The test samples in this study are Pt-on-SiO2 interdigitated comb structures. During testing all samples were immersed in saline for 150 days; for passive testing, the samples were left unbiased, whilst for active testing, samples were exposed to two different stress signals: a 5 V DC and a 5 Vp 500 pulses per second biphasic signal. All samples were monitored over time using impedance spectroscopy combined with optical inspection. After the first two weeks of immersion, delamination spots were observed on the Pt tracks for both passive and actively tested samples. Despite the delamination spots, the unbiased samples maintained high impedances until the end of the study. For the actively stressed samples, two different failure mechanisms were observed which were signal related. DC stressed samples showed severe parylene cracking mainly due to the electrolysis of the condensed water. Biphasically stressed samples showed gradual Pt dissolution and migration. These results contribute to a better understanding of the failure mechanisms of Pt tracks in active implants and suggest that new testing paradigms may be necessary to fully assess the long-term reliability of these devices.

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Section: Discussionmentioning

confidence: 68%

Effect of Signals on the Encapsulation Performance of Parylene Coated Platinum Tracks for Active Medical Implants

Nanbakhsh

Kluba

Pahl

et al. 2019

2019 41st Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC)

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“…Previously, Parylene-C micropore arrays have been reported [18,19,20,21] for cell separation. The reported Parylene-C micropore arrays with a large edge-to-edge space (10/12 μm [20], 11/12 μm [21], low porosity) were fabricated via micropatterning and etching with the photoresist or metal (aluminum [25,26] or titanium [27]) as the etching mask. Our previous study investigated SF 6 optimized oxygen plasma etching of Parylene-C [27] with micropatterned Ti acting as the etching mask, and this process was further utilized to try the fabrication of high-porosity Parylene-C micropore arrays in this study.…”

Section: Resultsmentioning

confidence: 99%

Microfabrication of Micropore Array for Cell Separation and Cell Assay

et al. 2018

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Micropore arrays have attracted a substantial amount of attention due to their strong capability to separate specific cell types, such as rare tumor cells, from a heterogeneous sample and to perform cell assays on a single cell level. Micropore array filtration has been widely used in rare cell type separation because of its potential for a high sample throughput, which is a key parameter for practical clinical applications. However, most of the present micropore arrays suffer from a low throughput, resulting from a low porosity. Therefore, a robust microfabrication process for high-porosity micropore arrays is urgently demanded. This study investigated four microfabrication processes for micropore array preparation in parallel. The results revealed that the Parylene-C molding technique with a silicon micropillar array as the template is the optimized strategy for the robust preparation of a large-area and high-porosity micropore array, along with a high size controllability. The Parylene-C molding technique is compatible with the traditional micromechanical system (MEMS) process and ready for scale-up manufacture. The prepared Parylene-C micropore array is promising for various applications, such as rare tumor cell separation and cell assays in liquid biopsy for cancer precision medicine.

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“…Unlike transwells, parylene-c is fabricated using soft lithography into regularly patterned substrates with ultra-thin submicron scale sections, mounted on a mesh frame to provide mechanical strength. Submicron regions are permeable to water and water-soluble ions that makes it optimal for diffusion systems [32]. Initial results from this trial show hESC-RPE seeded onto parylene-C membranes were well-tolerated when subretinally inserted into 5 patients with advanced AMD.…”

Section: Biomaterials For Dry Amdmentioning

confidence: 99%

Biomaterials Targeting AMD: Are We There Yet?

Lawless¹,

Hidalgo-Alvarez²,

Haneef³

2020

Preprint

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Age-related macular degeneration (AMD) is the leading cause of central blindness in developed countries. It affects people mainly over the age of 50 years. It is a disease of the macula, an area of the retina responsible for sharp central vision. It particularly affects the Bruch’s membrane (BM); a layer in the retina that acts as the basement upon which retinal pigment epithelial cells (RPE) attach and survive. The pathology of AMD is not fully understood, but age is considered the main risk factor. There are two forms; nonexudative, leading to the end-stage of the disease, called nonexudative (or dry) AMD (90% of cases) where fatty deposits called drusen form under the RPE on top of the BM lifting off the RPE, and neovascular (or wet) AMD (10% of cases) where abnormal new blood vessels grow and push through the BM, bleeding in and disrupting the RPE. Neovascular AMD is well controlled with regular antiangiogenic drug injections of anti-vascular endothelial growth factor (anti-VEGF) into the eye, whereas there is no current treatment for nonexudative AMD. Many research groups across the world are working on a treatment for nonexudative AMD. This review discusses the research currently being conducted including cell therapies, development of cell transplantation membranes, targeting other disease structures in affected retina (i.e. drusen), and drug delivery to the retina using nanoparticles. Finally, we include our research contributing to the field; developing a bioactive membrane intended to function two-fold: target diseased structures and transplant healthy RPE to the desired area.

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Techniques and Considerations in the Microfabrication of Parylene C Microelectromechanical Systems

Cited by 112 publications

References 109 publications

Effect of Signals on the Encapsulation Performance of Parylene Coated Platinum Tracks for Active Medical Implants

Effect of Signals on the Encapsulation Performance of Parylene Coated Platinum Tracks for Active Medical Implants

Microfabrication of Micropore Array for Cell Separation and Cell Assay

Biomaterials Targeting AMD: Are We There Yet?

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