Simple colorimetric or fluorescent analysis of small molecules based-on the interaction between DNA aptamers and unmodified gold nanoparticles

Title
Simple colorimetric or fluorescent analysis of small molecules based-on the interaction between DNA aptamers and unmodified gold nanoparticles
Authors
김연석S. Chin정종수
Keywords
sensor; aptamer; gold nanoparticle
Issue Date
2011-12
Publisher
The Second Nano Today Conference, 2011
Abstract
We developed simple aptamer-based colorimetric or fluorescent detection methods for lowweight molecules using unmodified gold nanoparticles (umAuNPs). This method was relied on the different electrostatic interactions of DNA aptamers on the surface of umAuNPs in the absence or presence of target molecules. In colorimetric assay, the aggregation of umAuNPs was prevented due to a stabilizing effect of aptamers adsorbed on umAuNPs at high salt concentration. However, addition of targets into the AuNPs solution triggered the aggregation of AuNPs because the competitive interaction of target to its aptamer induced the displacement of DNA aptamer from umAuNPs, subsequently the color change of the mixture from red to purple was happened. As a result, the red-to-purple color change was proportional to the concentration of targets and it was easily observed to micro-molar level by naked eye. It was also verified that the color change of AuNPs solution was not occurred in the addition of other structurally similar compounds. In fluorescent analysis, DNA aptamers were immobilized on quantum dots (QDs), and QDs conjugated ssDNA was adsorbed on the surface of umAuNPs. Subsequently the fluorescence of QDs was effectively quenched by AuNPs due to fluorescence resonance energy transfer (FRET) of QDs to AuNPs. In the presence of targets, the QDs conjugated aptamers was detached from AuNPs by target induced conformational change of aptamers consequently the fluorescence of QDs was recovered proportional to the target concentration. These homogeneous detection manners were very simple and fast, therefore, they are useful for the on-site detection of small molecules.
URI
http://pubs.kist.re.kr/handle/201004/41433
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KIST Publication > Conference Paper
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