A simple and direct electrochemical detection of interferon-gamma using its RNA and DNA aptamers

作者：Min Kyoungin; Cho Minseon; Han Se Young; Shim Yoon Bo; Ku Jakang; Ban Changill^*

来源：Biosensors and Bioelectronics, 2008, 23(12): 1819-1824.

DOI：10.1016/j.bios.2008.02.021

• tuberculosis
• interferon-gamma (IFN-gamma)
• electrochemical impedance spectroscopy
• RNA aptamer
• DNA aptamer

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.

• 出版日期2008-7-15