INTRODUCTION Aptamers are DNA or RNA ligands that recognize a specific target molecule with comparable affinity and specificity to antibody. Electrochemical aptamer sensor has several advantages at the point of thermal stability, ease of chemical modification, and miniaturization. To construct electrochemical aptamer sensors, various redox probes modified aptamers have been reported. However, still there are limitation in their application in the practical fields, including the modification method, redox potential, etc.. We previously reported on the application of novel redox probe, the pre-functionalized amine reactive phenazine ethosulfate; 1-[3-(Succinimidyloxycarbonyl)propoxy]-5-ethylphenazinium triflate (amine reactive PES: arPES) to prepare glucose dehydrogenase which showed quasi direct electron transfer1. Thanks to the simple and reproducible modification procedure, arPES modification is versatile method to prepare redox probe modified enzymes. This success prompted us to prepare and application of arPES modified aptamers. In this study, we prepared arPES modified aptamers and their electrochemical properties were investigated, aiming their potential applications to develop aptamer based washing free electrochemical biosensing system. METHODS and RESULTS As the aptamer, we used Vascular endothelial growth factor (VEGF)-binding aptamer. VEGF is an important target for diagnosis of certain diseases such as cancer or age-related eye disease. Therefore, rapid and sensitive detection is crucial for treatment of anti-VEGF drugs. We used G-quadruplex forming VEGF aptamer2. After the modification by arPES, 5′ thiol- or 3′ amine- harboring VEGF aptamer was immobilized on gold electrode. Cyclic voltammetry analyses revealed the observation of redox peaks of PES, indicating modification of aptamer with arPES successfully prepared the electrochemically active aptamer, which can be detected by the electrode. The addition of VEGF sample in the solution resulted in the change of the peak current observed by square wave voltammetry, indicating that the potential application of arPES modified aptamer to construct washing free electrochemical biosensing system.

Preparation of novel redox dye modified aptamers and their application to construct wash-free electrochemical biosensing technologies

2019 Spring National Meeting

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