PVP-coated graphene oxide for selective determination of ochratoxin A via quenching fluorescence of free aptamer

In the past few years, graphene oxide (GO) has emerged as a unique platform to develop DNA-based biosensors. This takes advantage of the DNA adsorption and fluorescence quenching property of GO.The adsorbed DNA probes can be desorbed from the GO surface in the presence of target analytes, producing fluorescence signal. In addition to this initial design, many other strategies have been reported including the use of aptamers, molecular beacons, and DNAzymes as probes, label-free detection, using the intrinsic fluorescence of GO and covalently linked DNA probes. The potential applications of DNA-functionalized GO range from environmental monitoring, cell imaging and biomedical diagnosis. In this review, we first summarize the fundamental surface interactions between DNA and GO and the related fluorescence quenching mechanism. Following that, the various sensor design strategies are critically compared. Problems at the current stages are described and a few future directions are also discussed.

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“…where its adsorption by GO was inhibited by ochratoxin A [96]. The detection limit was 1.9 μM with high specificity.…”

Section: Aspergillus Ochraceus and Penicillium Verrucosum A Fam-labementioning

confidence: 88%

Fluorescent sensors using DNA-functionalized graphene oxide

et al. 2014

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“…Comparing with the other aptamer-based methods for OTA detection [24][25][26][27][28][29][30][31][32][33][34][35][36][37][38], the sensitivity of our strategy is better than that of the methods using gold nanoparticles (limit of detection (LOD), 22 nM) [33], graphenes (1.9 μM) [29], carbon nanotubes (LOD, 24.5 nM) [38], and fluorescence ploarization (LOD, 5 nM) [22], but lower than that of some reported electrochemical methods [30], which allowed the detection of OTA at concentration lower than 1 nM. Some research groups recently reported the LOD of OTA reached 0.5 [27] or 0.25 pM [28] by using signal amplification strategy or nanomaterials in the aptamer-based assays.…”

Section: Screening the Labeling Sitesmentioning

confidence: 99%

“…The DNA aptamer for OTA has a high binding affinity, and the dissociation constant reaches about 50 nM [21,23]. Many aptamer-based methods for OTA analysis recently have been reported [24][25][26][27][28][29][30][31][32][33][34][35][36][37][38]. These methods have involved colorimetric, electrochemical, fluorescent, and chromatographic approaches.…”

Section: Introductionmentioning

confidence: 99%

Fluorescent sensing ochratoxin A with single fluorophore-labeled aptamer

2013

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We explored a fluorescent strategy for sensing ochratoxin A (OTA) by using a single fluorophore-labeled aptamer for detection of OTA. This method relied on the change of the fluorescence intensity of the labeled dye induced by the specific binding of the fluorescent aptamer to OTA. Different fluorescein labeling sites of aptamers were screened, including the internal thymine bases, 3′-end, and 5′-end of the aptamer, and the effect of the labeling on the aptamer affinity was investigated. Some fluorophorelabeled aptamers showed a signal-on or signal-off response. With the fluorescent aptamer switch, simple, rapid, and selective sensing of OTA at nanomolar concentrations was achieved. OTA spiked in diluted red wine could be detected, showing the feasibility of the fluorescent aptamer for a complex matrix. This method shows potential for designing aptamer sensors for other targets.

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“…One of the most important effects observed for the combination of a polymer with GO in an optical sensor based on uorescence detection has been reported by Sheng et al 188 They developed a simple method to detect ochratoxin A (OTA) using graphene oxide as a quencher of the uorescence of carboxyl uorescein (FAM) attached to a toxin-specic aptamer. OTA is one of the most abundant food-contaminating mycotoxins which can cause severe effects on human health.…”

Section: 25187mentioning

confidence: 99%