A simple and direct electrochemical detection of interferon-gamma using its RNA and DNA aptamers.
Tuberculosis is the most frequent cause of infection-related death worldwide. We constructed a simple and direct electrochemical sensor to detect interferon (IFN)-gamma, a selective marker for tuberculosis pleurisy, using its RNA and DNA aptamers. IFN-gamma was detected by its 5'-thiol-modified aptamer probe immobilized on the gold electrode. Interaction between IFN-gamma and the aptamer was recorded using electrochemical impedance spectroscopy and quartz crystal microbalance (QCM) with high sensitivity. The RNA-aptamer-based sensor showed a low detection limit of 100 fM, and the DNA-aptamer-based sensor detected IFN-gamma to 1 pM in sodium phosphate buffer. With QCM analysis, the aptamer immobilized on the electrode and IFN-gamma bound to the aptamer probe was quantified. This QCM result shows that IFN-gamma exists in multimeric forms to interact with the aptamers, and the RNA aptamer prefers the high multimeric state of IFN-gamma. Such a preference may describe the low detection limit of the RNA aptamer shown by impedance analysis. In addition, IFN-gamma was detected to 10 pM by the DNA aptamer in fetal bovine serum, a mimicked biological system, which has similar components to pleural fluid.
Min
Kyoungin
K
Department of Chemistry, Pohang University of Science and Technology, San31, Hyojadong, Pohang, Gyeongbuk 790-784, South Korea.
Cho
Minseon
M
Han
Se-Young
SY
Shim
Yoon-Bo
YB
Ku
Jakang
J
Ban
Changill
C
D052157:Aptamers, Nucleotide / Q000737:chemistry* / Q000235:genetics; D015374:Biosensing Techniques / Q000295:instrumentation*; D004563:Electrochemistry / Q000295:instrumentation*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D007371:Interferon-gamma / Q000032:analysis* / Q000235:genetics
D052157:Aptamers, Nucleotide; D007371:Interferon-gamma