Target-induced structure switching of a hairpin aptamer for the fluorescence detection of zeatin

Abstract

Zeatin (ZT) is a type of cytokinin which plays important roles in the proliferation and differentiation of plants cells. Here, we describe a fluorometric method for the detection of ZT, based on target-induced structure switching of a hairpin aptamer. The signal probe, an FAM-labeled aptamer, hybridizes partially with BHQ-2-labeled DNA and the fluorescence intensity of FAM is quenched by the approaching BHQ-2. With the addition of the target, the aptamer binds to ZT with high specificity and the BHQ-2-labeled DNA is released. Thus, the fluorescence intensity of the FAM-labeled aptamer is recovered and ZT can be quantitatively determined by monitoring the fluorescence signal change. This proposed method shows good sensitivity with a detection limit as low as 135 nM for ZT detection. In comparison to the previously reported ZT detection strategies based on graphene oxide (GO), this biosensor exhibits excellent selectivity. Moreover, this method has great potential for parallel analysis of different aptamer-based target molecules.