G-quadruplex-based assay combined with aptamer and gold nanoparticles for Escherichia coli K88 determination
A colorimetric method was developed using G-quadruplex and gold nanoparticles (AuNPs) for determination of Escherichia coli K88 ( ETEC K88 ). It was composed of two modules: (1) an aptamer as biorecognizing element and (2) a capturing DNA (modified with AuNPs at 5′) as a transducer. In the absence o...
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Veröffentlicht in: | Mikrochimica acta (1966) 2020-05, Vol.187 (5), p.308-308, Article 308 |
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Format: | Artikel |
Sprache: | eng |
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Zusammenfassung: | A colorimetric method was developed using G-quadruplex and gold nanoparticles (AuNPs) for determination of
Escherichia coli K88
(
ETEC K88
). It was composed of two modules: (1) an aptamer as biorecognizing element and (2) a capturing DNA (modified with AuNPs at 5′) as a transducer. In the absence of target bacteria, the aptamer can form stable double strands with capturing DNA, preventing the binding of capturing DNA to the G-quadruplex. However, the double strands of capturing DNA and aptamer are untied due to the stronger binding of aptamers to bacteria in the presence of target bacteria. As a result, the G-quadruplex binds to capture DNA and leads to the aggregation and color change of AuNPs, which can be monitored by a spectrophotometer or visualization. The quantitative determination was achieved by monitoring the optical density change of AuNPs solution at 524 nm after target addition. Under optimal conditions, the method has a low detection limit (1.35 × 10
2
CFU mL
−1
) and a linear response in the range 10
2
to 10
6
CFU mL
−1
.
Graphical abstract
The manuscripts describe a colorimetric method for the detection of
ETEC K88
by using intermolecular G-quadruplex to induce the agglomeration of gold nanoparticles, which can be directly used to determine the presence of bacteria with our naked eyes. |
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ISSN: | 0026-3672 1436-5073 |
DOI: | 10.1007/s00604-020-04291-x |