by Keyword: Ochratoxin A
Yang, Cheng, Lates, Vasilica, Prieto-Simón, Beatriz, Marty, Jean-Louis, Yang, Xiurong, (2012). Aptamer-DNAzyme hairpins for biosensing of Ochratoxin A Biosensors and Bioelectronics 32, (1), 208-212
We report an aptasensor for biosensing of Ochratoxin A (OTA) using aptamer-DNAzyme hairpin as biorecognition element. The structure of this engineered nucleic acid includes the horseradish peroxidase (HRP)-mimicking DNAzyme and the OTA specific aptamer sequences. A blocking tail captures a part of these sequences in the stem region of the hairpin. In the presence of OTA, the hairpin is opened due to the formation of the aptamer–analyte complex. As a result, self-assembly of the active HRP-mimicking DNAzyme occurs. The activity of this DNAzyme is linearly correlated with OTA concentration up to 10 nM, showing a limit of detection of 2.5 nM.
JTD Keywords: Ochratoxin A, Aptamer, G-quadruplex, DNAzyme, Hairpin
Barthelmebs, L., Jonca, J., Hayat, A., Prieto-Simon, B., Marty, J. L., (2011). Enzyme-Linked Aptamer Assays (ELAAs), based on a competition format for a rapid and sensitive detection of Ochratoxin A in wine 
Food Control , 22, (5), 737-743
Ochratoxin A (OTA) is one of the most important mycotoxins because of its high toxicity to both humans and animals and its occurrence in a number of basic foods and agro-products. The need to develop high-performing methods for OTA analysis able to improve the traditional ones is evident. In this work, through in vitro SELEX (Systematic Evolution of Ligands by EXponential enrichment) two aptamers, designated H8 and H12 were produced that bind with nanomolar affinity with Ochratoxin A (OTA). Two strategies were investigated by using an indirect and a direct competitive Enzyme-Linked Aptamer Assay (ELAA) and were compared to the classical competitive Enzyme-Linked Immunosorbent Assay (ELISA) for the determination of OTA in spiked red wine samples. The limit of detection attained (1 ng/mL), the midpoint value obtained (5 ng/mL) and the analysis time needed (125 min) for the real sample analysis validate the direct competitive ELAA as useful screening tool for routine use in the control of OTA level in wine.
JTD Keywords: Competitive Enzyme-Linked Aptamer Assay (ELAA), DNA aptamer, Ochratoxin A, SELEX, Wine analysis
