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Updated: Jan 11, 2026
Design and Development of Aptamer–Gold Nanoparticle Based Colorimetric Assays for In-the-field Applications
Published on: June 23, 2016
Dual-Mode Plasmonic Colorimetric/Photothermal Aptasensor for OTA: Based on a Mn2+-Powered DNA Walker for Mediating
Zhi Li1, Quan Liu1, Hongwei Zhang1
1Shanxi Center for Testing of Functional Agro-Products, Longcheng Campus, Shanxi Agricultural University, No. 79, Longcheng Street, Taiyuan 030031, China.
Abstract:
The sensitive and efficient detection of ochratoxin A (OTA) is critical for protecting agricultural ecosystems and public health. A dual-mode plasmonic colorimetric/photothermal aptasensor, based on a Mn2+-powered DNA walker for mediating gold nanobipyramid (AuNB) growth, is proposed for OTA detection in this study. In sensing the target OTA, the walking DNA (W-DNA) on the magnetic walker probe was independent and then the environment-friendly Mn2+ powered the generation of DNAzyme, where abundant thiol-modified DNA (DNA-SH) was produced by autonomous walking. The positively related DNA-SH level could mediate AuNB growth and reflect dual-mode plasmonic signals. Ultrasensitivity is demonstrated with a limit of detection (LOD) value of 48.6 pg mL-1 for colorimetric mode and 37.6 pg mL-1 for photothermal mode. The aptasensor exhibited high specificity (with cross-reactivity values below 6.2% for other analytes) and high reliability for OTA detection. The requisite practicability and accessibility are verified via its application in agricultural byproduct samples. The findings of this study offer an alternative and efficient biosensing pathway for improving detection performance, enabling green, enzyme-free, homogeneous, and dual-mode strategies for monitoring other pollutants.
