School of Traditional Chinese Medicine, Capital Medical University, Beijing 100069, China; Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100193, China; College of Traditional Chinese Medicine, Xinjiang Medical University, Urumqi 830011, China.
Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100193, China.
Food Chem. 2023 Mar 1;403:134375. doi: 10.1016/j.foodchem.2022.134375. Epub 2022 Sep 21.
Trace detection of ochratoxin A (OTA) in foods is essential to mitigate risks to human health. Herein, a label-free electrochemical (EC) aptasensor based on dual-signal amplification of Nafion dispersed multi-walled carbon nanotubes (Nafion-MWCNTs) and Au nanopopcorns was developed for ultrasensitive detection of OTA. Nafion solution prevented the leaching of MWCNTs, and the Nafion-MWCNTs modified screen-printed carbon electrode (SPCE) acted as the sensing substrate which facilitated the uniform distribution of the electrodeposited Au nanopopcorns. The in-situ generated Au nanopopcorns could not only load a large amount of aptamers for specific identification of OTA, but also promote the electron transfer of the sensing platform. The incorporation of Nafion-MWCNTs and Au nanopopcorns realized dual-amplification of the aptasensor due to the enhanced conductivity and the increased electroactive surface area of the electrode. The modified electrodes were characterized through scanning electron microscopy, X-ray photoelectron spectroscopy and EC evaluation. Under optimal conditions, the electrochemical impedance spectroscopy (EIS) was measured for the determination of OTA. The as-fabricated Au nanopopcorns/Nafion-MWCNTs impedimetric aptasensor displayed excellent sensitivity with a detection limit as low as 1 pg/mL and a wide linear range of 1 pg/mL-10 ng/mL for OTA. Practical application of the aptasensor in the spiked malt samples achieved satisfactory recoveries of 89.82-95.65 %, which was also successfully verified to detect OTA in eleven batches of actual malt samples collected from the local market. The creative aptasensor is simple, cost-effective, sensitive, and accurate, showing great promise for on-site monitoring of other trace contaminants in foods by simply replacing the aptamers.
痕量检测食品中的赭曲霉毒素 A (OTA)对于减轻对人类健康的风险至关重要。在此，开发了一种基于 Nafion 分散多壁碳纳米管 (Nafion-MWCNTs) 和 Au 纳米爆米花的双信号放大的无标记电化学 (EC) 适体传感器，用于超灵敏检测 OTA。Nafion 溶液防止了 MWCNTs 的浸出，并且 Nafion-MWCNTs 修饰的丝网印刷碳电极 (SPCE) 充当了传感基底，有利于均匀分布电沉积的 Au 纳米爆米花。原位生成的 Au 纳米爆米花不仅可以负载大量适体用于 OTA 的特异性识别，而且还可以促进传感平台的电子转移。由于电极的导电性增强和有效表面积增加，Nafion-MWCNTs 和 Au 纳米爆米花的结合实现了适体传感器的双重放大。通过扫描电子显微镜、X 射线光电子能谱和 EC 评价对修饰电极进行了表征。在最佳条件下，通过电化学阻抗谱 (EIS) 测量来测定 OTA。所制备的 Au 纳米爆米花/Nafion-MWCNTs 阻抗适体传感器表现出优异的灵敏度，检测限低至 1 pg/mL，OTA 的线性范围为 1 pg/mL-10 ng/mL。该适体传感器在掺假麦芽样品中的实际应用获得了 89.82%-95.65%的令人满意的回收率，并且还成功验证了从当地市场采集的 11 批实际麦芽样品中检测 OTA。该创造性的适体传感器简单、经济高效、灵敏且准确，通过简单地替换适体，有望用于现场监测食品中的其他痕量污染物。
