A sensitive electrochemical aptasensor based on water soluble CdSe quantum dots (QDs) for thrombin determination

Yanfen Li, Min Han, Hongyan Bai, Yong Wu, Zhihui Dai, Jianchun Bao

Research output: Contribution to journalArticlepeer-review

40 Scopus citations

Abstract

A novel aptamer biosensor with easy operation and good sensitivity, specificity, stability and reproducibility was developed by immobilizing the aptamer on water soluble CdSe quantum dots (QDs) modified on the top of the glassy carbon electrode (GCE). Methylene blue (MB) was intercalated into the aptamer sequence and used as an electrochemical marker. CdSe QDs improved the electrochemical signal because of their larger surface area and ion centers of CdSe QDs may also had a major role on amplifying the signal. The higher ion concentration caused more combination of aptamer which caused larger signal. The thrombin was detected by differential pulse voltammetry (DPV) quantitatively. Under optimal conditions, the two linear ranges were obtained from 3 to 13 μg mL-1 and from 14 to 31 μg mL-1, respectively. The detection limit was 0.08 μg mL-1 at 3σ. The constructed biosensor had better responses compared with that in the absence of the CdSe QDs immobilizing. The control experiment was also carried out by using BSA, casein and IgG in the absence of thrombin. The results showed that the aptasensor had good specificity, stability and reproducibility to the thrombin. Moreover, the aptasensor could be used for detection of real sample with consistent results in comparison with those obtained by fluorescence method which could provide a promising platform for fabrication of aptamer based biosensors.

Original languageEnglish
Pages (from-to)7058-7063
Number of pages6
JournalElectrochimica Acta
Volume56
Issue number20
DOIs
StatePublished - 1 Aug 2011
Externally publishedYes

Keywords

  • Aptamer
  • Biosensor
  • CdSe quantum dots
  • Methylene blue
  • Thrombin

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