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Updated: Aug 22, 2025
A Method for Selecting Structure-switching Aptamers Applied to a Colorimetric Gold Nanoparticle Assay
Published on: February 28, 2015
A novel ultrasensitive and fast aptamer biosensor of SEB based on AuNPs-assisted metal-enhanced fluorescence
Xueyu Chang1, Yaqian Cheng1, Xinke Wang1
1Tianjin Key Laboratory of Risk Assessment and Control Technology for Environment and Food Safety, Tianjin Institute of Environmental and Operational Medicine, Tianjin 300050, People's Republic of China.
Abstract:
A fluorescent biosensor strategy was developed in combination with immunomagnetic separation for rapid and sensitive detection of staphylococcal enterotoxin B (SEB). Magnetic nanoparticles (MNPs) modified with aptamer of SEB could capture the SEB. Then the gold nanoparticles (AuNPs) fluorescent probe was added and a "sandwich structure" was formed between AuNPs, SEB and MNPs. The MNPs-SEB-AuNPs structure could be separated with an additional magnetic field, which resulted the lower signals of AuNPs fluorescent probe. In optimal conditions, the current method displayed a broad quantitative range from 100 to 107 fg/mL and the limit of detection was 3.43 fg/mL. The recovery of SEB-spiked milk samples ranged from 92.00 to 119.00 %, which revealed that the developed method had great accuracy. Furthermore, the method was fast and economical for ultrasensitive detection. Therefore, the fluorescent biosensor based on MNPs-AuNPs is promising for the detection of other environmental and food pollutants.
