A Lateral Flow Strip Based Aptasensor for Detection of Ochratoxin A in Corn Samples

Abstract

Ochratoxin A (OTA) is a mycotoxin identified as a contaminant in grains and wine throughout the world, and convenient, rapid and sensitive detection methods for OTA have been a long-felt need for food safety monitoring. Herein, we presented a new competitive format based lateral flow strip fluorescent aptasensor for one-step determination of OTA in corn samples. Briefly, biotin-cDNA was immobilized on the surface of a nitrocellulose filter on the test line. Without OTA, Cy5-labeled aptamer combined with complementary strands formed a stable double helix. In the presence of OTA, however, the Cy5-aptamer/OTA complexes were generated, and therefore less free aptamer was captured in the test zone, leading to an obvious decrease in fluorescent signals on the test line. The test strip showed an excellent linear relationship in the range from 1 ng·mL−1 to 1000 ng·mL−1 with the LOD of 0.40 ng·mL−1, IC15 value of 3.46 ng·mL−1 and recoveries from 96.4% to 104.67% in spiked corn samples. Thus, the strip sensor developed in this study is an acceptable alternative for rapid detection of the OTA level in grain samples.

The end user sensor tree: An end-user friendly sensor database

“…This could be altered if a smartphone camera is used as a detector which has been the case for both pesticides (Comina et al, 2016) and mycotoxins (Machado et al, 2018). In fact when reviewing the portable axes of the TEST system, colorimetric techniques currently prevail with microorganisms (Liu et al, 2015) (Wu et al, 2015) (Jiang et al, 2016) and mycotoxins (Zhang et al, 2018) (Liu et al, 2017) (Song et al, 2014) being the most mentioned targets. As for the semi-portable section almost all reports fall in the semi-quantitative group and of these more than half of the reports used a variant of nanotechnology often using EC technology such as Palmsens for detection.…”

Semi‐quantitative and quantitative detection of ochratoxin A in agricultural by‐products using a self‐assembling immunochromatographic strip

“…produced a multi‐component chromatographic test strip for the simultaneous detection of AFB 1 , OTA, and ZEN, in which the LOD for OTA was 0.5 ng mL −1 24 . Furthermore, several other novel IC methods have recently been developed to test for OTA contamination 25–27 …”

“…24 Furthermore, several other novel IC methods have recently been developed to test for OTA contamination. [25][26][27] Currently, the rapid detection technology is facing a variety of challenges, such as increased pollution, expensive testing equipment, professional operation requirements, high purity standards, and a large number of samples that require testing. 28,29 Comparing all of the OTA detection methods discussed above, the IC method allows for both the semi-quantitative and quantitative detection of OTA with many advantages.…”

Antibody Microarray Immunoassay for Simultaneous Quantification of Multiple Mycotoxins in Corn Samples

“…LOD is an important parameter to reflect the sensitivity of mycotoxin detection methods. For example, the LOD of AFB 1 was 14 ng/mL using fluorescent sensor systems [ 27 ], and 1.6 ng/mL using aptamer-based fluorescent assay [ 28 ]; the LOD of OTA was 8.7 nM using nitrogen doped carbon dots and the silver nanoparticles based fluorescence method [ 29 ], 0.40 ng/mL by lateral flow strip based aptasensor [ 30 ], and 2.57 ng/mL using a novel biosensor platform [ 31 ]; the LOD of ZEN was 0.114 ng/mL using an indirect competitive enzyme-linked immunosorbent assay [ 32 ], 3.2 ng/mL using a novel recombinant cell fluorescence biosensor [ 33 ], and 0.5 ng/mL using aptamer-based fluorescence assay [ 34 ]; and the LOD of FB 1 was 11.1 ng/mL using microarray-based immunoassay with synthetic mimotopes [ 35 ], and 1.15 ng/mL by indirect ELISA [ 36 ]. The LODs of the current assay (AFB 1 : 0.21 ng/mL, OTA: 0.19 ng/mL, ZEN: 0.09 ng/mL, and FB 1 : 0.24 ng/mL) are relatively low, which justifies its higher sensitivity.…”