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Updated: Jul 30, 2025
Design and Development of Aptamer–Gold Nanoparticle Based Colorimetric Assays for In-the-field Applications
Published on: June 23, 2016
A Colorimetric Aptasensor for Ochratoxin A Detection Based on Tetramethylrhodamine Charge Effect-Assisted Silver
Xiaoyan Yang1, Rong Huang1, Lulu Xiong1
1Key Laboratory of Luminescent and Real-Time Analytical Chemistry, Ministry of Education, Institute for Clean Energy and Advanced Materials, School of Materials and Energy, Southwest University, Chongqing 400715, China.
Abstract:
A novel colorimetric aptasensor based on charge effect-assisted silver enhancement was developed to detect ochratoxin A (OTA). To achieve this objective, gold nanoparticles (AuNPs), which can catalyze silver reduction and deposition, were used as the carrier of the aptamers tagged with a positively charged tetramethylrhodamine (TAMRA). Due to the mutual attraction of positive and negative charges, the TAMRA attracted and retained the silver lactate around the AuNPs. Thus, the chance of AuNP-catalyzed silver reduction was increased. The charge effect-assisted silver enhancement was verified by tagging different base pair length aptamers with TAMRA. Under optimized conditions, the as-prepared OTA aptasensor had a working range of 1 × 102-1 × 106 pg mL-1. The detection limit was as low as 28.18 pg mL-1. Moreover, the proposed aptasensor has been successfully applied to determine OTA in actual samples with satisfactory results.
