Aptamer-conjugated Gold Nanoparticles for Biosensing and Enzymatic Inhibition
Date Issued
2010
Date
2010
Author(s)
Chen, Shih-Ju
Abstract
In this thesis, a highly selective and sensitive optical biosensor using aptamer-modified gold nanoparticles (Apt-Au NPs) was developed for bio-analytical applications, including the determination of biomolecules and the inhibition of enzyme activity. Combinating with the properties of target-induced conformational changes of aptamers and the salt-induced aggregation of Au NPs, a colorimetric approach using Apt-Au NPs had been designed for the determination of adenosine and its phosphorylated derivatives. The sensitivity of this sensing assay could be improved by evaluating the effects of several parameters, such as the ionic strength, the aptamer density on the Au NPs, and the presence of additives. In addition, I also developed a label-free fluorescence analytical sensor—comprising an adenosine-binding aptamer (AptAdo), platelet-derived growth factor (PDGF)-binding aptamer (AptPDGF), Au NPs, and the DNA-binding dye Oligreen (OG)—for the determination of adenosine. In the sensing mixture, AptAdo and AptPDGF are for the recognition of adenosine and for the amplification of fluorescence signal, respectively. The LOD for adenosine could been further lowered when using AptAdo-Au NPs for the enrichment of adenosine. To demonstrate the inhibition of enzymatic activity by Apt-Au NPs, I selected two aptamers, RT1t49 (Aptpol) and ODN 93 (AptRH), that binds to polymerase site (pol) and RNase H site (RH) of Human immunodeficiency virus type 1 reverse transcriptase (HIV-1 RT), respectively. With the advantages of specific, increased inhibition, AptRH-Au NPs and Aptpol-Au NPs were considered as the highly effective inhibitors for HIV-1 RT polymerization. The stability and specificity of the 40Aptpol-Au NPs remain almost the same in the presence of DNase I and BSA, respectively. Moreover, I found that the combination of 40AptRH-Au NPs with Aptpol led to the synergistic inhibition, which hold great potential to be an effective and alternative drug for HIV. Apt-Au NPs indeed could be applied to the bio-analytical tools for the detection, diagnosis and therapeutic of diseases.
Subjects
aptamer
gold nanoparticles (Au NPs)
biosensor
G-quadruplex
adenosine
adenosine triphosphate (ATP)
Human immunodeficiency virus type 1 reverse transcriptase (HIV-1 RT)
polymerase
inhibition
SDGs
Type
thesis
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