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7. Electrochemical
Detection of Specific Gene Related to NPT II Using Methylene Blue
and p-Phenylenediamine–modified Glassy Carbon Electrode
Guiyun Xu,*† JInshi Fan,** Yu Yin***
* College of Chemistry and Molecular Engineering, Qingdao University
of Science and Technology, 266042 Qingdao, China
**College of Chemistry and Chemical Engineering, University of
Science and Technology, 266042 Qingdao, China
*** Shandong Shanshui Cement Group Limited Company (Shanshui
Industry Garden)，250307 Jinan, China
Guiyun Xu: phone number: +86-532-84022949 e-mail:
xuguiyun@qust.edu.cn
Abstract:
P-phenylenediamine (PPD) was introduced onto an electrochemical
oxidized glassy carbon electrode using water-soluble
1-ethyl-3-(3-dimethyl-aminopropyl) carbodiimide hydrochloride (EDC)
and N-hydroxysuccinimide (NHS). DNA was then covalently
immobilized onto the PPD modified GCE with surface-bound primary
amino group in the presence of EDC. Cyclic voltammetry and
differential pulse voltammetry were used to characterize the DNA
modified electrodes using methylene blue (MB) as electro-active
indicator. The results showed that ssDNA immobilized using P-phenylenediamine
as connector (ssDNA/PPD/GCE) could hybridize with target ssDNA
effectively. The ssDNA/PPD/GCE was successfully employed for the
selective detection of NPT II gene (presented in almost all the
genetically modified plants) in a fragment of 20-base
oligodeoxynucleotides sample. The electro-reduction signal of MB
was related to the NPT II gene concentration over the range of
1.2×10-10 mol/L to 2.5×10-9 mol/L.
KEYWORDS: P-phenylenediamine; DNA; Methylene blue; NPT II
gene.
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