Blank peak current-suppressed electrochemical aptameric sensing platform for highly sensitive signal-on detection of small molecule.
In this contribution, an electrochemical aptameric sensing scheme for the sensitive detection of small molecules is proposed using adenosine as a target model. A ferrocene (Fc)-functionalized thiolated aptamer probe is adapted and immobilized onto an electrode surface. Introducing a recognition site for EcoRI into the aptamer sequence not only suppresses the peak current corresponding to blank sample but also provides a signal-on response mechanism. In the absence of adenosine, the aptamer can fold into a hairpin structure and form a cleavable double-stranded region. Fc is capable of being removed from electrode surface by treatment with endonuclease, and almost no peak current is observed. The adenosine/aptamer binding induces the conformational transition of designed aptamer, dissociating the cleavable double-stranded segment. Therefore, the integrated aptamer sequence is maintained when exposing to endonuclease, generating a peak current of Fc. Utilizing the present sensing scheme, adenosine even at a low concentration can give a detectable current signal. Thus, a detection limit of 10(-10) M and a linear response range from 3.74×10(-9) to 3.74×10(-5) M are achieved. The proposed proof-of-principle of a novel electrochemical sensing is expected to extend to establish various aptameric platforms for the analysis of a broad range of target molecules of interest.
Zhang
Songbai
S
State Key Laboratory for Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, PR China.
Hu
Rong
R
Hu
Peng
P
Wu
Zai-Sheng
ZS
Shen
Guo-Li
GL
Yu
Ru-Qin
RQ
D000241:Adenosine / Q000032:analysis; D052157:Aptamers, Nucleotide / Q000737:chemistry*; D015374:Biosensing Techniques / Q000379:methods*; D004553:Electric Conductivity; D017097:Electric Impedance; D055664:Electrochemical Techniques / Q000379:methods*; D009690:Nucleic Acid Conformation; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
D052157:Aptamers, Nucleotide; D000241:Adenosine