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Title:Micron-scale flexible electronics for detection of reactive oxygen species for in vivo applications
Author(s):Wilson, Rebekah C.
Director of Research:Scheeline, Alexander
Doctoral Committee Chair(s):Scheeline, Alexander
Doctoral Committee Member(s):Bailey, Ryan C.; Wieckowski, Andrzej; Feng, Albert S.
Department / Program:Chemistry
Degree Granting Institution:University of Illinois at Urbana-Champaign
cytochrome c
superoxide dismutase
Abstract:The design, fabrication and modification of a flexible sensor for the detection OF superoxide for investigations within a Mongolian gerbil’s cochlea were optimized. Electron beam deposition was used to deposit a thin film of titanium followed by a layer of gold on a Kapton™ surface. Prior to deposition, oxygen plasma was used to planarize the Kapton surface for a smoother gold surface. Typical lithography procedures were used to pattern gold electrodes, yielding up to four electrodes. Delamination of gold from the binding layer was found minimized by the use of a desiccator, but was not completely eliminated. It was also found that exposure of thin gold films to oxygen plasma yielded the cleanest gold surfaces for self assembled monolayers. Laser ablation was used to abstract the sensors from the excess substrate yielding a flexible circuit that is 2.5 cm in length and only 200 M across the sensing tip. Initial attempts to reproduce a cited procedure to utilize immobilized superoxide dismutase (SOD) for the working electrode was unsuccessful. However, Cytochrome C was immobilized using 3,3’–Dithiodipropionic acid di(N-hydroxysuccinimide ester) (DTSP) and found to yield appropriate responses when exposed to superoxide. Brief, but promising, attention is given to the initial developments in using potassium superoxide as a more reliable superoxide source than the xanthine/xanthine oxidase system. The sensor is tested in the presence of common biological interferents. NADH, citric acid, and uric acid, showed negligible effects on the sensor’s function. While hydrogen peroxide is known to reduce Cytochrome C, its effect in the presence superoxide are nearly immeasurable. However, H2O2 hinders the ability of superoxide dismutase to return signal fully to baseline. Glucose is present in cochlear fluids and showed a 16% decrease in current when introduced in the presence of superoxide and, like hydrogen peroxide, hindered the effectiveness of superoxide dismutase in returning signal to baseline. The sensor was placed through the round window of a gerbil cochlea to examine the fitting constraints. The 200 m tip allowed for ample space. The sensor showed expected responses when superoxide was diffused through the cochlea, proving ability of detection within natural fluids.
Issue Date:2010-08-20
Rights Information:Copyright 2010 Rebekah Christine Koch Wilson
Date Available in IDEALS:2010-08-20
Date Deposited:2010-08

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