"Biossensor Impedimétrico para detecção de Saxitoxina"

Autores: Pablo Serrano A., Gisele Elias Nunes, Ivan H. Bechtold

Instituições: Universidade Federal de Santa Catarina

Autor apresentador: Pablo Serrano Arambulo

Resumo: Saxitoxin (STX) is a neurotoxin mainly produced by certain marine dinoflagellates, as well as, certain cyanobacteria, for example Cylindrospermapsis raciborskii [1, 2]. A high density of this cyanobacteria was detected in the Lagoa do Peri, which is the largest freshwater body of the city of Florianópolis, State of Santa Catarina [1]. Thus, the development of rapid and sensitive methods for STX detection is strongly required for health care and ecosystem pollution. Between the different methods for toxins detection, the electrochemical biosensors, represent a promising alternative for such applications. In this work, an electrochemical aptasensor based on the use of an aptamer (APT) [2] for detection of STX is presented. First, the specific APT for STX was modified with thiol to immobilize on a gold electrode by Casting through Au-S interaction. For the detection process, the biosensors Au/APT/MCH were incubated in various concentrations of STX. Electrochemical detection step in aptasensors Au/APT/STX was investigated by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Control experiments were used with other nonspecific toxins. Finally, our sensor was able to detect concentrations of STX in the range of 3.0μg/L, which is the maximum permissible STX value for potable water standards [3].

References

[1]Teive, L. F. et al.; Biotemas, 21(2), 133-143, (2008)

[2]Wang, L.H. et al.; Toxicon 101 41–47 (2015).

[3]Derberdt, G. L. B. et al; Florações de cianobactérias e sua inserção na legislação brasileira, 1- 5, (2004).

Key words: biosensor, Saxitoxin, electrochemical impedance, aptamer

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