Facile and Cost-Effective Detection of Saxitoxin Exploiting Aptamer Structural Switching

Karol Alfaro1, Paulina Bustos1, Ciara O´Sullivan2 and Pablo Conejeros1*

1Centro de Investigación y Gestión de Recursos Naturales, Facultad de Ciencias, Universidad de Valparaíso, Gran
  Bretaña 1111, Valparaíso, Chile
2Nanobiotechnology and Bioanalysis Group, Department of Chemical Engineering, Universitat Rovira i Virgili, 43007
 ES-Tarragona, Spain

Article history:
Received September 22, 2014
Accepted April 28, 2015

Key words:
red tide, paralytic shellfish poison, aptamers, saxitoxin, high resolution melting

A simple method to detect saxitoxin (STX), one of the main components of the paralytic shellfish poison from red tide, has been developed. By using a next generation dye for double-stranded DNA we were able to differentiate fluorescence from STX-binding aptamers when exposed to different concentrations of STX, suggesting a change in aptamer folding upon target binding. The developed method is extremely rapid, only requiring small sample volumes, with quantitative results in the concentration range of 15 ng/mL to 3 μg/mL of STX, with a detection limit of 7.5 ng/mL.

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