A challenging choice of aptamer for the selective enrichment of ochratoxin A

Diazo-functionalised immunoelectrochemical sensor for the detection of ochratoxin a in foods

Ochratoxin A (OTA) is a toxic fungal metabolite that is commonly found in cereals and animal feed. It is economically damaging and potentially hazardous to human health. Herein, we propose an electrochemical immunosensor for the rapid detection of OTA using anti-OTA antibodies and diazonium-functionalized, screen-printed electrodes. We attached 4-aminobenzoic acid to an electrode surface, activated the carboxyl groups on the surface with carbodiimide, and attached an antibody to the diazo layer. Subsequently, we used bovine serum protein as a blocker to prevent non-specific antigens from binding to the antibody. We evaluated the performance of the sensor by cyclic voltammetry, electrochemical impedance spectroscopy, and differential pulse voltammetry. The sensor is highly specific and sensitive, has good linear responses in the range 20-200 ng/mL, a limit of detection of 0.5 ng/mL, and good recoveries of 90.5%-100.9% in spiked samples. It can be stored at 4 °C for approximately 2 weeks, and is highly stable, with a current response variation of no more than 4.6%.

A novel approach to design electrochemical aptamer-based biosensor for ultrasensitive detecting of zearalenone as a prevalent estrogenic mycotoxin

BACKGROUND

Zearalenone is a well-known estrogenic mycotoxin produced by Fusarium species, a serious threat to the agricultural and food industries worldwide. Zearalenone, with its known metabolites, are biomarkers of exposure to certain fungi, primarily through food. It has considerable toxic effects on biological systems due to its carcinogenicity, mutagenicity, renal toxicity, teratogenicity, and immunotoxicity.

INTRODUCTION

This study aims to design a simple, quick, precise, and cost-effective method on a biosensor platform to evaluate the low levels of this toxin in foodstuffs and agricultural products.

METHODS

An aptamer-based electrochemical biosensor was introduced that utilizes screen-printed gold electrodes instead of conventional electrodes. The electrode position process was employed to develop a gold nanoparticle-modified surface to enhance the electroactive surface area. Thiolated aptamers were immobilized on the surface of gold nanoparticles, and subsequently, the blocker and analyte were added to the modified surface. In the presence of a redox probe, electrochemical characterization of differential pulse voltammetry, cyclic voltammetry, and electrochemical impedance spectroscopy were used to investigate the various stages of aptasensor fabrication.

RESULTS

The proposed aptasensor for zearalenone concentration had a wide linear dynamic range covering the 0.5 pg/mL to 100 ng/mL with a 0.14 pg/mL detection limit. Moreover, this aptasensor had high specificity so that a non-specific analyte cannot negatively affect the selectivity of the aptasensor.

CONCLUSION

Overall, due to its simple design, high sensitivity, and fast performance, this aptasensor showed a high potential for assessing zearalenone in real samples, providing a clear perspective for designing a portable and cost-effective device.