Truncated DNA aptamer for rapid fluorometric detection of the lethal toxin α-amanitin

Abstract

Mushroom poisoning is the main cause of foodborne poisoning in China. Of these deaths, 90% are caused by the consumption of amatoxins-containing mushrooms. The aim of this study was to investigate the mechanism by which a novel recognition factor-aptamer recognizes the deadly amatoxin known as α-amanitin, and to establish a method for the rapid detection of the α-amanitin. Apt-20 was obtained and characterized to possess the same affinity as the original chain with significantly higher specificity. A rapid fluorescence assay for α-amanitin was developed using Apt-20. The assay system was designed using the principle that the complementary chain of α-amanitin competes with the aptamer for binding, resulting in a change in the fluorescence signal value. The α-amanitin concentration showed a linear relationship with the fluorescence signal in the range of 51.25–800 ng/mL (Y = 1.243x + 351.6, R2 = 0.991) with a detection limit of 51.25 ng/mL. The specificity of the assay system was good. The recovery rates from urine were 93.88%–95.01%, with an accompanying detection time of 1 h, indicating it can achieve the rapid detection of α-amanitin in urine samples.