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Lee YK, Yu KJ, Song E, Farimani AB, Vitale F, Xie Z, Yoon Y, Kim Y, Richardson A, Luan H, Wu Y, Xie X, Lucas TH, Crawford K, Mei Y, Feng X, Huang Y, Litt B, Aluru NR, Yin L, Rogers JA. Dissolution of Monocrystalline Silicon Nanomembranes and Their Use as Encapsulation Layers and Electrical Interfaces in Water-Soluble Electronics. ACS NANO 2017; 11:12562-12572. [PMID: 29178798 PMCID: PMC5830089 DOI: 10.1021/acsnano.7b06697] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
The chemistry that governs the dissolution of device-grade, monocrystalline silicon nanomembranes into benign end products by hydrolysis serves as the foundation for fully eco/biodegradable classes of high-performance electronics. This paper examines these processes in aqueous solutions with chemical compositions relevant to groundwater and biofluids. The results show that the presence of Si(OH)4 and proteins in these solutions can slow the rates of dissolution and that ion-specific effects associated with Ca2+ can significantly increase these rates. This information allows for effective use of silicon nanomembranes not only as active layers in eco/biodegradable electronics but also as water barriers capable of providing perfect encapsulation until their disappearance by dissolution. The time scales for this encapsulation can be controlled by introduction of dopants into the Si and by addition of oxide layers on the exposed surfaces.The former possibility also allows the doped silicon to serve as an electrical interface for measuring biopotentials, as demonstrated in fully bioresorbable platforms for in vivo neural recordings. This collection of findings is important for further engineering development of water-soluble classes of silicon electronics.
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Affiliation(s)
| | | | - Enming Song
- Department of Materials Science and Engineering, Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USADepartment of Materials Science, Fudan University, Shanghai 200433, China
| | | | - Flavia Vitale
- Department of Neurology, Department of Physical Medicine and Rehabilitation, Center for Neuroengineering and Therapeutics, Perelman School of Medicine University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Zhaoqian Xie
- Department of Civil and Environmental Engineering, Mechanical Engineering, and Materials Science and Engineering, Northwestern University, Evanston, IL 60208, USA AML, Department of Engineering Mechanics, Center for Mechanics and Materials Tsinghua University, Beijing 100084, China
| | - Younghee Yoon
- Department of Materials Science and Engineering, Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Yerim Kim
- Department of Materials Science and Engineering, Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Andrew Richardson
- Department of Neurosurgery, Center for Neuroengineering and Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Haiwen Luan
- Department of Civil and Environmental Engineering, Mechanical Engineering, Materials Science and Engineering, Northwestern University, Evanston, IL 60208, USA
| | - Yixin Wu
- Department of Materials Science and Engineering, Northwestern University, Evanston, IL 60208 USASchool of Materials Science and Engineering, Tsinghua University, Beijing 100084 China
| | - Xu Xie
- Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801 USA
| | - Timothy H. Lucas
- Department of Neurosurgery, Center for Neuroengineering and Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Kaitlyn Crawford
- Materials Science and Engineering, University of Central Florida, Florida 32816 USA
| | - Yongfeng Mei
- Department of Materials Science, Fudan University, Shanghai 200433, China
| | - Xue Feng
- AML, Department of Engineering Mechanics, Center for Mechanics and Materials, Tsinghua University, Beijing 100084, China
| | - Yonggang Huang
- Department of Civil and Environmental Engineering, Mechanical Engineering, Materials Science and Engineering, Northwestern University, Evanston, IL 60208, USA
| | - Brian Litt
- Department of Neurology, Center for Neuroengineering and Therapeutics, Perelman School of Medicine, Department of Bioengineering, School of Engineering and Applied Sciences, Penn Center for Health, Devices & Technology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Narayana R. Aluru
- Mechanical Science and Engineering, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Lan Yin
- Corresponding Author: To whom correspondence should be addressed. John A. Rogers (), Lan Yin ()
| | - John A. Rogers
- Corresponding Author: To whom correspondence should be addressed. John A. Rogers (), Lan Yin ()
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The exit strategy: Pharmacological modulation of extracellular matrix production and deposition for better aqueous humor drainage. Eur J Pharmacol 2016; 787:32-42. [PMID: 27112663 DOI: 10.1016/j.ejphar.2016.04.048] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Revised: 04/20/2016] [Accepted: 04/22/2016] [Indexed: 01/28/2023]
Abstract
Primary open angle glaucoma (POAG) is an optic neuropathy and an irreversible blinding disease. The etiology of glaucoma is not known but numerous risk factors are associated with this disease including aging, elevated intraocular pressure (IOP), race, myopia, family history and use of steroids. In POAG, the resistance to the aqueous humor drainage is increased leading to elevated IOP. Lowering the resistance and ultimately the IOP has been the only way to slow disease progression and prevent vision loss. The primary drainage pathway comprising of the trabecular meshwork (TM) is made up of relatively large porous beams surrounded by extracellular matrix (ECM). Its juxtacanalicular tissue (JCT) or the cribriform meshwork is made up of cells embedded in dense ECM. The JCT is considered to offer the major resistance to the aqueous humor outflow. This layer is adjacent to the endothelial cells forming Schlemm's canal, which provides approximately 10% of the outflow resistance. The ECM in the TM and the JCT undergoes continual remodeling to maintain normal resistance to aqueous humor outflow. It is believed that the TM is a major contributor of ECM proteins and evidence points towards increased ECM deposition in the outflow pathway in POAG. It is not clear how and from where the ECM components emerge to hinder the normal aqueous humor drainage. This review focuses on the involvement of the ECM in ocular hypertension and glaucoma and the mechanisms by which various ocular hypotensive drugs, both current and emerging, target ECM production, remodeling, and deposition.
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Pittman KM, MacMillan-Crow LA, Peters BP, Allen JB. Nitration of manganese superoxide dismutase during ocular inflammation. Exp Eye Res 2002; 74:463-71. [PMID: 12076090 DOI: 10.1006/exer.2002.1141] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Reactive nitrogen species, in particular, peroxynitrite (ONOO(-)) have been proposed to play an important role in the pathogenesis of endotoxin-induced uveitis (EIU). Tyrosine nitration by ONOO(-) has been shown in other model systems to inhibit the activity of the superoxide anion quenching enyzme, manganese superoxide dismutase (MnSOD), perhaps contributing to progression of disease. In this study, it is confirmed through immunoanalysis that nitrated proteins are produced during EIU, and furthermore, that MnSOD is a target of nitration during the inflammatory response. In addition, through microsequencing analyses, nitrated albumin--apparent in both control and EIU eyes--was identified. Positive immunostaining of nitrated proteins was seen in the ciliary epithelium, inflammatory cells, and protein exudate of eyes from rats injected with endotoxin. Incubation of nitrotyrosine immunoprecipitates from the iris and ciliary body (ICB) with a polyclonal antibody against MnSOD revealed that nitrated MnSOD was present only in the ICB of EIU rats. When the total activity of the enzyme was examined, it was observed that despite the presence of nitrated MnSOD, activity was increased relative to control. Analysis of MnSOD mRNA and protein from the ICB of both groups demonstrated an increase in mRNA expression and consequently a three- to five-fold increase in MnSOD protein in EIU rats as compared to control rats. Further examination of MnSOD protein expression through immunohistochemistry noted enhanced immunostaining in the ciliary epithelium of eyes of EIU rats. Additional investigation of a 70 kDa band apparent in nitrotyrosine immunoprecipitates from the ICB of control and EIU rats revealed that the plasma protein albumin is nitrated as well. This protein is present as a result of the breakdown of the blood-aqueous barrier during inflammation. In summary, two endogenous nitration targets, albumin and MnSOD, were identified. Nitrated MnSOD appears to be specifically targeted to the ICB during inflammation, underscoring the importance of the interface in EIU. Furthermore, the expression and activity of the enzyme is increased in the ICB during EIU, perhaps regulating reactive nitrogen species produced within the cells. This study implicates ONOO(-) in the pathogenesis of EIU and imparts the putative role MnSOD plays in disease resolution.
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Affiliation(s)
- K M Pittman
- Department of Anatomy, Physiological Sciences and Radiology, College of Veterinary Medicine, North Carolina State University, 4700 Hillsborough Street, Raleigh, NC 27606, USA
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Holmér AK, Hård S, Helgason G, Tønjum A. Design, calibration, and testing of a laser flare meter. APPLIED OPTICS 1994; 33:2611-2619. [PMID: 20885615 DOI: 10.1364/ao.33.002611] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
A laser flare meter, insensitive to corneal, lens, and eye background scattering and calibrated by measurements and theoretical modeling, is reported. Calibration measurements and theoretical calculations of light scattering from albumin solutions were found to agree within the limits of error. The results from in vivo measurements of normal eyes of different ages agreed well with normal protein content of aqueous humor. A special aperture design was used to reduce the unwanted background scattering resulting in signal-to-background ratios between 1:1 and 1:3 for normal eyes. Moderately cataractous eyes, with increased scattering from the lens, could be measured with sufficient accuracy. The reproducibility was measured to be ~ 12%. We studied how the flare is affected by sex, right/left eye, eye color, time of day, pupillary dilation, and an intraocular pressure measurement. No differences of practical importance were found.
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Abstract
The effect of anterior chamber puncture on cloxacillin concentration in the rabbit eye after intravenous injection was studied using a radioactive tracer method. The enhancement in drug concentration caused by paracentesis was most immediate and significant in the iris-ciliary body preparation. It was soon followed by high cloxacillin concentration in the aqueous humour, which contributed to elevated cloxacillin levels in the cornea, lens and anterior vitreous body, when compared to normal material. Contrary to normal eyes, cloxacillin concentration in the cornea of the punctured eyes was higher than in the limbal area. The morphological changes occurring after paracentesis are discussed. The breakdown of the hydrodynamic equilibrium in the eye, suggested as the only change after paracentesis by Raviola (1974), cannot merely explain the cloxacillin concentration changes measured in the punctured eye.
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