Biosensors for environmental monitoring via bioinhibition

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Title Biosensors for environmental monitoring via bioinhibition
Publication Type dissertation
School or College College of Science
Department Chemistry
Author Wang, Tao
Date 2017
Description Biosensors are devices that recognize, analyze, and transduce signal for detection via biological materials with bio-recognition properties. As of now, almost all kinds of biomaterials, including microbial cells, organelles, proteins, and nucleic acid, have been used for biosensors. In this dissertation, two kinds of biomaterials, enzymes and organelles, have been used for novel biosensor development. The primary focus of the research is the inhibition mechanism of laccase and mitochondria by different environmental toxins, like arsenic and pesticides. In Chapter 2, a laccase-based biosensor was developed for arsenic sensing. Inhibition of oxygen reduction by arsenic was observed electrochemically via laccase immobilized with anthracene-modified multiwalled carbon nanotubes on a Toray carbon paper electrode. First, it was found that laccase is inhibited by arsenite and arsenate, and the inhibition mechanism was further determined as mixed inhibition (with preference to an uncompetitive inhibition model). Second, the laccase-modified electrodes were then fabricated into a self-powered biosensor with flavin-adenine-dinucleotide-dependent glucose dehydrogenase-based bioanodes. The biosensor was operated at 10% of its maximum current and demonstrated a detection limit of 13 µM for arsenite and 132 µM for arsenate. In Chapter 3, a mitochondrial paper-based biosensor was fabricated. Coupled mitochondria were isolated from bovine heart and demonstrated an amperometrical detection limit of 20 nM for malathion, a common pesticide. The inhibition mechanism by malathion to mitochondrial metabolism was studied electrochemically and was determined to be uncoupling rather than inhibition. In Chapter 4, the inhibition mechanism of mitochondria by rotenone, carboxin, and antimycin was studied. It was also discovered that the synergy between riboflavin derivatives and ubiquinone can be altered by using different solvents during the electrode fabrication process. A further study indicated that lipid membrane is capable of altering the reaction dominance between ubiquinone and riboflavin derivatives. Finally, it was discovered that mitochondria release riboflavin derivatives under inhibition and it is believed that this alteration of the micro-environment was the cause of the change in mitochondrial electrochemistry when mitochondria were inhibited.
Type Text
Publisher University of Utah
Subject Analytical chemistry; Biosensor; Inhibition; Laccase; Mitochondria
Dissertation Name Doctor of Philosophy
Language eng
Rights Management ©Tao Wang
Format application/pdf
Format Medium application/pdf
ARK ark:/87278/s6rv4t29
Setname ir_etd
ID 1347735
Reference URL https://collections.lib.utah.edu/ark:/87278/s6rv4t29
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