Selection and characterization of dimethylindole red DNA aptamers for the development of light-up fluorescent probes

Publication date: 1 June 2017
Source:Talanta, Volume 168
Author(s): Hongyan Wang, Jine Wang, Qinglin Wang, Xing Chen, Min Liu, Hongxia Chen, Renjun Pei
To develop novel label-free light-up probes with improved performance characteristics and low background, we selected DNA aptamers for dimethylindole red (DIR) by a modified affinity chromatography based SELEX method. DIR is an anionic propylsulfonate substituted red-emitting dye derivative of thiazole orange and exhibited weak fluorescence in fluid solution and in the presence of dsDNA. After 14 rounds of selection, a shortened 42-mer DNA aptamer with sub-micromolar dissociation constant (Kd=0.65±0.17μM) was selected. The fluorescent intensity of DIR was dramatically enhanced in the presence of the specific aptamer. The aptamer gave a 140-fold fluorescence enhancement in a saturated concentration. The DIR-aptamer pair could be potentially used as novel light-up fluorescent probe to construct sensors for various applications.

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