Page 89 - 《渔业研究》2025年第6期

780 渔 业 研 究 第 47 卷

Rapid detection of tetrodotoxin by aptamer-based gold nanoparticles
colorimetric method

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LIU Zijing ，CAI Shuilin ，HUANG Wenshu ，CHEN Xiaohong ，QIAO Kun ，XU Min ，LIU Zhiyu 2*
(1. Fisheries College, Jimei University, Xiamen 361021, China;
2. Key Laboratory of Cultivation and High-value Utilization of Marine Organisms in Fujian Province,
Fisheries Research Institute of Fujian, Xiamen 361013, China)
Abstract: [Background] Tetrodotoxin (TTX), a potent neurotoxin widely distributed in marine organisms
such as pufferfish, poses a significant public health threat caused by accidental consumption of TTX-contamin-
ated aquatic products. This toxin can induce respiratory failure and fatal outcomes, underscoring the urgent need
for highly efficient and sensitive detection technologies to ensure food safety. [Objective] This study aims to
construct a simple, visual colorimetric detection method based on aptamer-modified gold nanoparticles (AuNPs)
sensor. [Methods] AuNPs were prepared by the sodium citrate reduction method, and characterized by trans-
mission electron microscopy (TEM) and ultraviolet-visible (UV-Vis) absorption spectroscopy. Aptamer (Apt)
were adsorbed onto the surface of AuNPs through electrostatic interaction, which protected AuNPs from ag-
gregation and color change in high-salt environments to a certain extent. When TTX existed in the system, it
specifically bound to Apt, causing AuNPs to aggregate and change color. After optimizing the experimental
conditions, the ratio of A 620 /A 521 at different TTX concentrations was determined by UV spectroscopy to estab-
lish a linear regression equation, calculate the limit of detection, and perform specificity analysis and spike-re-
covery experiments. [Results] The prepared AuNPs had uniform particle size (approximately 15 nm) and a
maximum absorption peak at 521 nm. Based on the result, a visual TTX detection method using an Apt-AuNPs
colorimetric sensor was constructed. The optimal experimental parameters determined through condition optim-
ization were as follows: AuNPs volume fraction of 45%, NaCl concentration of 300 mmol/L, NaCl reaction time
of 10 min, Apt concentration of 80 nmol/L, Apt incubation time of 25 min, TTX-Apt incubation time of 20 min,
TTX-Apt incubation temperature of 10 °C, and TTX-Apt pH of 5. Under the optimized conditions, TTX detec-
tion showed a good linear relationship between TTX concentration (19.53~312.5 ng/mL) and the corresponding
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A 620 /A 521 value, with a linear correlation coefficient (R ) of 0.995 7 and a limit of detection of 12.97 ng/mL. In
the spike recovery experiments, the recovery rates of TTX ranged from 104.2% to 108.4%, with relative stand-
ard deviations (RSD) of 0.85%~1.77%. [Conclusion] The study developes an aptamer-based AuNPs colorimet-
ric method for TTX detection, which is expected to provide a simple, rapid, visual, and accurate approach for
TTX analysis.
Key words: tetrodotoxin (TTX); aptamer (Apt); gold nanoparticles (AuNPs); colorimetry