Development of a Nafion-MWCNTs and in-situ generated Au nanopopcorns dual-amplification electrochemical aptasensor for ultrasensitive detection of OTA. (1st March 2023)

• Record Type: Journal Article
• Authors: Hou, Yujiao; Long, Nan; Xu, Qingbin; Li, Ying; Song, Pengyue; Yang, Minghan; Wang, Jiabo; Zhou, Lidong; Sheng, Ping; Kong, Weijun
• Is Part Of: Food chemistry. Volume 403(2023)
• Publication Date: 2023-03-01
• Subjects: Electrochemical aptasensor -- Multi-walled carbon nanotubes -- Au nanopopcorns -- Dual-signal amplification -- Ochratoxin A -- Malt; Food -- Analysis -- Periodicals; Food -- Composition -- Periodicals; 664
• DOI: 10.1016/j.foodchem.2022.134375
• Languages: English
• ISSNs: 0308-8146

Abstract

Highlights: A label-free electrochemical aptasensor was developed for OTA detection. No extra coupling medium was involved for immobilizing the aptamers. Nafion-MWCNTs and in-situ generated Au nanopopcorns achieved dual-amplification. The aptasensor displayed excellent sensitivity and wide linear range for OTA. Practical application in malt samples confirmed great promise for more contaminants. Abstract: 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.