Li Xiaoyan, Falcone Natashya, Hossain M Nur, Kraatz Heinz-Bernhard, Chen Xiaojun, Huang He
School of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, 211816, PR China; College of Chemistry and Molecular Engineering, Nanjing Tech University, Nanjing, 211816, PR China.
Department of Physical and Environmental Sciences, University of Toronto Scarborough, 1065 Military Trail, Toronto, ON M1C 1A4, Canada.
Talanta. 2021 May 1;226:122183. doi: 10.1016/j.talanta.2021.122183. Epub 2021 Feb 5.
Ochratoxin A (OTA) is one of the most abundant mycotoxins that contaminate various food products. Herein, we propose a novel label-free impedimetric electrochemical sensor consisting of chitosan/dipeptide nanofibrous hydrogel and immobilized DNA probes with OTA aptamer for the detection of OTA. The thin film of chitosan/dipeptide nanofibrous hydrogel was used as sensing interface and carrier for hybridization chain reaction (HCR) of OTA aptamer and DNA2 strand to form DNA concatemer. The concatemer was dissociated to single-stranded DNA (ssDNA) in the presence of target OTA, and the signal amplification was further implemented by introducing RecJ exonuclease, which could digest the single-stranded DNA resulting in OTA recycle. Electrochemical impedance spectroscopy (EIS) has been employed to characterize the properties of the fabricated sensor. A linear detection range of 0.1-100 ng mL was obtained for OTA with a low detection limit of 0.03 ng mL. Furthermore, the developed sensor was demonstrated in white wine to detect OTA, indicating that the proposed impedimetric sensor has a promising potential application in the food industry.
赭曲霉毒素A（OTA）是污染各种食品的最常见霉菌毒素之一。在此，我们提出了一种新型的无标记阻抗型电化学传感器，它由壳聚糖/二肽纳米纤维水凝胶和固定有OTA适体的DNA探针组成，用于检测OTA。壳聚糖/二肽纳米纤维水凝胶薄膜用作传感界面和OTA适体与DNA2链杂交链式反应（HCR）的载体，以形成DNA串联体。在目标OTA存在下，串联体解离为单链DNA（ssDNA），并通过引入RecJ核酸外切酶进一步实现信号放大，该酶可消化单链DNA导致OTA循环利用。采用电化学阻抗谱（EIS）对制备的传感器性能进行表征。OTA的线性检测范围为0.1 - 100 ng/mL，检测下限低至0.03 ng/mL。此外，所开发的传感器在白葡萄酒中用于检测OTA，表明所提出的阻抗型传感器在食品工业中具有广阔的潜在应用前景。
