Colorimetric and photothermal dual-mode aptasensor with redox cycling amplification for the detection of ochratoxin A in corn samples

Jian Tang; Jiali Liu; Fupeng Wang; Yaochun Yao; Rong Hu

doi:10.1016/j.foodchem.2023.137968

Colorimetric and photothermal dual-mode aptasensor with redox cycling amplification for the detection of ochratoxin A in corn samples

Food Chem. 2024 May 1:439:137968. doi: 10.1016/j.foodchem.2023.137968. Epub 2023 Nov 11.

Authors

Jian Tang¹, Jiali Liu², Fupeng Wang², Yaochun Yao³, Rong Hu⁴

Affiliations

¹ National Engineering Research Center of Vacuum Metallurgy, Faculty of Metallurgy and Energy Engineering, Kunming University of Science and Technology, Kunming 650093, Yunnan, China.
² College of Chemistry and Chemical Engineering, Yunnan Normal University, Kunming, Yunnan 650500, China.
³ National Engineering Research Center of Vacuum Metallurgy, Faculty of Metallurgy and Energy Engineering, Kunming University of Science and Technology, Kunming 650093, Yunnan, China. Electronic address: yaochun9796@163.com.
⁴ College of Chemistry and Chemical Engineering, Yunnan Normal University, Kunming, Yunnan 650500, China. Electronic address: hudierong_168@163.com.

PMID: 38043279
DOI: 10.1016/j.foodchem.2023.137968

Abstract

Ochratoxin A (OTA) detection is critical for public health safety. This study proposes a G-quadruplex-Hemin/iodide (G4-Hemin/I^-)-mediated non-enzyme redox cycling amplification (RCA) system for dual-modal (colorimetric and photothermal thermometer) OTA analysis. The proposed aptasensor platform for point-of-care testing employs a common thermometer for quantitative signal readouts. The OTA aptamer folds into a G4 structure, which significantly enhances the catalytic activity in the presence of I^- after RCA reaction. Moreover, a notable temperature enhancement causes color changes, providing an ultrasensitive and label-free platform for OTA detection. Further, the designed sensor was applied to OTA content determination in corn samples and achieved satisfactory results compared to a commercial enzyme-linked immunoassay kit. The proposed dual-mode aptasensor is simple, highly sensitive (1 pg/mL for colorimetric method, 0.8 pg/mL for photothermal method), selective, and suitable for low-cost instrument-free bioanalysis in low-resource settings.

Keywords: Dual-mode aptasensor; Ochratoxin A; POCT; Photothermal platform; Redox cycling amplification (RCA).

MeSH terms

Aptamers, Nucleotide* / chemistry
Biosensing Techniques* / methods
Colorimetry / methods
Hemin
Limit of Detection
Ochratoxins* / analysis
Zea mays

Substances

ochratoxin A
Hemin
Aptamers, Nucleotide
Ochratoxins