Fluorescent strip sensor for rapid determination of toxins

Abstract

Here, we report a simple fluorescent strip sensor based on aptamer-quantum dots technology that can meet toxin monitoring demands using ochratoxin A (OTA) as a model toxin. The limit of the detection (LOD) for the fluorescent strip was 1.9 ng mL(-1), while the time needed for the detection is only 10 min; this conforms to the standards of World Health Organization (WHO) or better. Overall functional parameters are also better than the analogous characteristics of gold nanoparticle strips. High selectivity was maintained as well, making them suitable for the samples with complex solution composition.

Fluorescent sensing ochratoxin A with single fluorophore-labeled aptamer

“…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. Although the sensitivity was not as high as for methods using signal amplification or nanomaterials, our strategy provides a simple way for sensing OTA at a useful concentration level.…”

“…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.…”

Analytical performances of a DNA-ligand system using time-resolved fluorescence for the determination of ochratoxin A in wheat

“…Since its development in 2008, the OTA DNA aptamer has been integrated into several biosensor detection systems, including electrochemical [20][21][22][23][24], electrochemiluminescent [25,26], colorimetric [27,28] and fluorescent [29,30] platforms, enzyme-linked aptamer assays [17] and fluorescent test strips [31][32][33]. Moreover, affinity column systems based on OTA aptamers have been developed for clean-up of food extracts [16,[34][35][36].…”

Novel multiplex fluorescent immunoassays based on quantum dot nanolabels for mycotoxins determination

“…Colloidal semiconductor nanocrystal QDs are characterized by unique size-tunable optical properties which favor their use for biomedical diagnostics , Yezhelyev et al, 2007, molecular imaging (Liu et al, 2008, Ruan et al, 2007 and chemical analysis (Gill et al, 2008, Pinwattana et al, 2010, Vinayaka et al, 2009, Wang et al, 2011. They possess a broad absorbance band and a narrow size-dependent symmetrical sharply defined emission peak (Alivisatos et al, 2005, Chan et al, 2002, Jaiswal et al, 2003, Medintz et al, 2005.…”