Building and Testing of a MUHEG Capped Quantum Dot Lead Biosensor Specific Against Mercury Quenching
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Authors
Gerlach, Gary F., II
Issue Date
2008
Type
Thesis
Language
en_US
Keywords
Alternative Title
Abstract
Lead the believed oldest known metal presents many problems when introduced
into the body. The toxicity of lead arises from its ability to mimic other biologically
important metals. Despite the prevalence of lead toxicity and available resources many
fundamental questions about the biochemical processes responsible for lead toxicity
remain unanswered. Towards this aim a biosensor was designed and constructed to detect
subcellular distribution of lead ion. Biosensors have recently emerged as analytical
devices that couple a biomolecular recognition event with a physicochemical detection
element providing analyte detection. The functional specific design of metalloproteins
was selected to represent the backbone reporter element of the biosensor. Optical
physicochemical detection was emitted from quantum dots and measured through
fluorescence spectroscopy. The selectively designed lead-binding metalloprotein (PbBP)
was modified with a redox active ruthenium(II) metal complex at its amino-terminus.
When lead ion is bound to PbBP a conformational change results, allowing the metal
complex to donate an electron to the quantum dot attached at the carboxyl-terminus. The
electron transferred to the quantum dot decreases the fluorescence emitted, supplying a
measurable response known as the quench to be analyzed. Previous experiments have
seen an undesirable 90 % quenching responses due to mercury ion presence. In
addressing this problem a novel (l-Mercaptoundec-ll-yl)hexa(ethylene glycol) quantum
dot capping group (MUHEG) replaced the previously used metallothionein capping
group, and rectified the quenched response by ten fold.
Description
v, 35 p.
Citation
Publisher
Kalamazoo College
License
U.S. copyright laws protect this material. Commercial use or distribution of this material is not permitted without prior written permission of the copyright holder.