What question did this study set out to answer?

To develop a photoelectrochemical method for detecting ochratoxin A with high sensitivity and specificity.

February 8, 2026Journal of Agricultural and Food Chemistry4 citations

Polarity-Switching Photoelectrochemical Detection of Ochratoxin A Based on Target-Responsive Dendritic Mesoporous Silica Nanoparticle and Z-Scheme Hemin/HOF-101 Heterostructure

KXKe XiaoCentral South University of Forestry and Technology SHSitong HuangCentral South University of Forestry and Technology JSJia SunCentral South University of Forestry and Technology

Key Points

To develop a photoelectrochemical method for detecting ochratoxin A with high sensitivity and specificity.
Synthesis of aminated dendritic mesoporous silica nanoparticle (DMSN)
Encapsulation of hemin in the pores of DMSN sealed with OTA-specific aptamers
Measurement of photocurrent polarity changes as a response to OTA binding
Achieved a linear detection range of 10 pg mL-1 to 10 μg mL-1 for ochratoxin A
Limit of detection for OTA was 3.5 pg mL-1
Results from complex food matrices were comparable to those obtained from high-performance liquid chromatography (HPLC)

Abstract

A novel polarity-switching photoelectrochemical (PEC) sensing method was proposed for quantifying ochratoxin A (OTA). Aminated dendritic mesoporous silica nanoparticle (DMSN) with well-defined pores was synthesized to encapsulate hemin, and its pore channels were sealed by OTA-specific aptamers as gatekeepers. Specific binding of OTA to the aptamer induced conformational changes and aptamer dissociation, triggering the release of entrapped hemin. The released hemin was captured by a hydrogen-bonded organic framework (HOF-101) modified electrode, which switched the photocurrent polarity from cathodic to anodic, with the anodic signal linearly increasing with OTA concentration. Under optimized conditions, the method exhibited a linear range of 10 pg mL-1-10 μg mL-1 and a limit of detection (LOD) of 3.5 pg mL-1. Validated with camellia oil samples, its results were comparable to high-performance liquid chromatography (HPLC), verifying reliability for OTA detection in complex food matrices.

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