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With a recent shift to a more environmentally conscious society, low-carbon and non-carbon producing energy production methods are being investigated and applied all over the world. Of these methods, fuel cells show great potential for clean energy production. A fuel cell is an electrochemical energy conversion device which directly converts

With a recent shift to a more environmentally conscious society, low-carbon and non-carbon producing energy production methods are being investigated and applied all over the world. Of these methods, fuel cells show great potential for clean energy production. A fuel cell is an electrochemical energy conversion device which directly converts chemical energy into electrical energy. Proton exchange membrane fuel cells (PEMFCs) are a highly researched energy source for automotive and stationary power applications. In order to produce the power required to meet Department of Energy requirements, platinum (Pt) must be used as a catalyst material in PEMFCs. Platinum, however, is very expensive and extensive research is being conducted to develop ways to reduce the amount of platinum used in PEMFCs. In the current study, three catalyst synthesis techniques were investigated and evaluated on their effectiveness to produce platinum-on copper (Pt@Cu) core-shell nanocatalyst on multi-walled carbon nanotube (MWCNT) support material. These three methods were direct deposition method, two-phase surfactant method, and single-phase surfactant method, in which direct deposition did not use a surfactant for particle size control and the surfactant methods did. The catalyst materials synthesized were evaluated by visual inspection and fuel cell performance. Samples which produced high fuel cell power output were evaluated using transmission electron microscopy (TEM) imaging. After evaluation, it was concluded that the direct deposition technique was effective in synthesizing Pt@Cu core-shell nanocatalyst on MWCNTs support when a rinsing process was used before adding platinum. The peak power density achieved by the rinsed core-shell catalyst was 618 mW.cm-2 , 13 percent greater than that of commercial platinum-carbon (Pt/C) catalyst. Transmission electron microscopy imaging revealed the core-shell catalyst contained Pt shells and platinum-copper alloy cores. Rinsing with deionized (DI) water was shown to be a crucial step in core-shell catalyst deposition as it reduced the number of platinum colloids on the carbon nanotube surface. After evaluation, it was concluded that the two-phase surfactant and single-phase surfactant synthesis methods were not effective at producing core-shell nanocatalyst with the parameters investigated.
ContributorsAdame, Anthony (Author) / Madakannan, Arunachalanadar (Thesis advisor) / Peng, Xihong (Committee member) / Tamizhmani, Govindasamy (Committee member) / Arizona State University (Publisher)
Created2012
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Objective: Progressive accumulation of α-synuclein (α-syn) has been associated with Parkinson's disease (PD) and Dementia with Lewy body (DLB). The mechanisms through which α-syn leads to neurodegeneration are not completely clear; however, the formation of various oligomeric species have been proposed to play a role. Antibody therapy has shown effectiveness at

Objective: Progressive accumulation of α-synuclein (α-syn) has been associated with Parkinson's disease (PD) and Dementia with Lewy body (DLB). The mechanisms through which α-syn leads to neurodegeneration are not completely clear; however, the formation of various oligomeric species have been proposed to play a role. Antibody therapy has shown effectiveness at reducing α-syn accumulation in the central nervous system (CNS); however, most of these studies have been conducted utilizing antibodies that recognize both monomeric and higher molecular weight α-syn. In this context, the main objective of this study was to investigate the efficacy of immunotherapy with single-chain antibodies (scFVs) against specific conformational forms of α-syn fused to a novel brain penetrating sequence.

Method: We screened various scFVs against α-syn expressed from lentiviral vectors by intracerebral injections in an α-syn tg model. The most effective scFVs were fused to the cell-penetrating peptide penetratin to enhance transport across the blood–brain barrier, and lentiviral vectors were constructed and tested for efficacy following systemic delivery intraperitoneal into α-syn tg mice.

Result: Two scFVs (D5 and 10H) selectively targeted different α-syn oligomers and reduced the accumulation of α-syn and ameliorated functional deficits when delivered late in disease development; however, only one of the antibodies (D5) was also effective when delivered early in disease development. These scFVs were also utilized in an enzyme-linked immunosorbent assay (ELISA) assay to monitor the effects of immunotherapy on α-syn oligomers in brain and plasma.

Interpretation: The design and targeting of antibodies for specific species of α-syn oligomers is crucial for therapeutic immunotherapy and might be of relevance for the treatment of Lewy body disease.

ContributorsSpencer, Brian (Author) / Williams, Stephanie (Author) / Rockenstein, Edward (Author) / Valera, Elvira (Author) / Xin, Wei (Author) / Mante, Michael (Author) / Florio, Jazmin (Author) / Adame, Anthony (Author) / Masliah, Eliezer (Author) / Sierks, Michael (Author) / Ira A. Fulton Schools of Engineering (Contributor)
Created2016-06-16