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A Colorimetric Aptasensor for Ochratoxin A Detection Based on Tetramethylrhodamine Charge Effect-Assisted Silver Enhancement.

Xiaoyan YangRong HuangLulu XiongFeng ChenWei SunLing Yu
Published in: Biosensors (2023)
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 × 10 2 -1 × 10 6 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.
Keyphrases
  • gold nanoparticles
  • label free
  • sensitive detection
  • reduced graphene oxide
  • quantum dots
  • silver nanoparticles
  • loop mediated isothermal amplification
  • single molecule
  • fluorescent probe