Conjugated Polyelectrolyte and Aptamer Based Potassium Assay via Single‐ and Two‐Step Fluorescence Energy Transfer with a Tunable Dynamic Detection Range |
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Authors: | Bao Lam Nguyen Ji‐Eun Jeong In Hwan Jung Boram Kim Van Sang Le Inhong Kim Kwangseuk Kyhm Han Young Woo |
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Affiliation: | 1. Department of Nanofusion Engineering and Department of Cogno‐Mechatronics Engineering (WCU), Pusan National University, Miryang, Republic of Korea;2. Institute of Applied Materials Science, Vietnam Academy of Science and Technology, Ho Chi Minh City, Vietnam;3. Department of Chemistry, University of Chicago, Chicago, IL, USA;4. Department of Cogno‐Mechatronics Engineering, Physics Education and Physics, Pusan National University, Busan, Republic of Korea |
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Abstract: | A new potassium ion detection assay was developed using a dye‐labeled aptamer and conjugated polyelectrolyte (CPE) as a signaling platform via 1‐step and 2‐step fluorescence resonance energy transfer. Guanine‐rich K+‐specific aptamers were designed as K+ ion recognition species with 6‐carboxyfluorescein (6‐FAM) and 6‐carboxytetramethylrhodamine (6‐TAMRA) at both termini. In the presence of K+ ions, the aptamers undergo a conformational change from an unfolded to folded form by forming a G‐quadruplex with K+, bringing two dyes in proximity. FRET‐induced 6‐TAMRA emission was proportional to K+] in a range of 22.5 μm –100 mm in water without interference by the presence of excess Na+ ions (100 mm ). Upon the addition of CPE, a two‐step FRET process from CPE to 6‐TAMRA via 6‐FAM was enabled, showing an intensified 6‐TAMRA signal with K+ ions. The dynamic detection range and limit of detection (LOD) was fine‐tuned from ~millimolar to ~nanomolar concentrations of K+ by modulating the signal amplification effect of CPE. The LOD was determined to be ≈3.0 nm . This detection assay also showed high selectivity against other metal ions. This sensing scheme can be extended to the detection of a wide range of target materials by simply modifying the recognition aptamer sequence. |
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Keywords: | conjugated polyelectrolytes aptamers FRET potassium fluorescence |
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