Colorimetric Sensing of Creatinine by Cooperative Catalysis of Esterification and Hydrolysis on Bifunctionalized Gold Nanoparticles
Date Issued
2009
Date
2009
Author(s)
Chen, Chiu-Feng
Abstract
Gold nanoparticles (GNPs) exhibit intense red color due to the surface plasmon absorbance whose peak position is sensitive to the interparticle distance. By taking advantage of the color transition of red to blue associated with the dispersive to aggregated states of GNPs, many colorimetric sensing strategies have been developed.resented here is a novel approach that cooperatively catalytic esterification and hydrolysis are involved. We examine the model system using creatinine, which is a metabolite of muscle contraction and is cleared from the body by kidney via glomerular filtration. The concentrations of the serum or urinary creatinine are almost constant for healthy people such that the creatinine levels are used as an indicator to evaluate kidney function. GNPs are first bifunctionalilzed by ([15]crown-5)CH2O(CH2)4SH (denoted 15c5-C4-SH) and thioctic acid (TA). Secondly, esterification takes place and stabilizes GNPs when the bifunctionalized 15c5-C4-S/TA-GNPs are dissolved in a pH 2~5 methanol (containing ~10% water). In control experiments without esterification, hydrogen bonding at the carboxylic-moiety drives aggregation and destabilizes GNPs. For the sensing examination, creatinine is introduced in to esterified GNPs and a cooperatively catalytic hydrolysis leads to the aggregation of GNPs via the developed interparticle hydrogen bonding. Ultimately, rapid evaluation of kidney function by the naked-eye is successful through colorimetric sensing of creatinine with the use of the bifunctionalized-gold nanoparticle assay.
Subjects
Gold Nanoparticles
Cooperative Catalysis
Colorimetric Sensing
Creatinine
Type
thesis
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