%0 Journal Article
%T Development of a Fluorescent Biosensor Based on DNAzyme for Tracing the Release of Zinc in Maize Leaves.
%A Yan Y
%A Cai S
%A Zhao Y
%A Zhang Y
%A Wang X
%A Zhou N
%J J Agric Food Chem
%V 71
%N 18
%D 2023 May 10
%M 37125744
%F 5.895
%R 10.1021/acs.jafc.3c00508
%X A fluorescent biosensor for real-time monitoring the release of Zn2+ in plants was constructed through immobilization of DNAzyme-containing hairpin DNA on nanofertilizer ZnO@Au nanoparticles (ZnO@Au NPs). A specially designed hairpin DNA containing both DNAzyme and its substrate sequence, which was also labeled with 5'-FAM and 3'-SH groups, was modified on ZnO@Au NPs through the Au-S bond. The fluorescent signal of FAM was initially quenched by AuNPs. When Zn2+ was released from ZnO@Au NPs, DNAzyme was activated and the substrate sequence in hairpin DNA was cleaved. The restored fluorescent signal in Tris-HCl buffer (pH 6.5) was correlated with the concentration of the released Zn2+. The performance of the biosensor was first demonstrated in the solution. The linear detection range was from 50 nM to 1.5 μM, with a detection limit of 30 nM. The biosensor system can penetrate into maize leaves with ZnO@Au NPs. With the release of Zn2+ in leaves, the restored fluorescence can be imaged by a confocal laser scanning microscope and used for monitoring the release and distribution of Zn2+. This work may provide a novel strategy for tracing and understanding the mechanism of nanofertilizers in organisms.