Exo III-Catalyzed Release of a Zn2+-Ligation
DNAzyme to Drive the Strand Displacement Reaction and Gold Aggregation
for the Homogeneous Bioassay of Kanamycin Antibiotics
posted on 2021-08-26, 19:33authored byYiming Xie, Haiyan Wang, Xinyue Yuwen, Guosong Lai
Herein,
we combine the exonuclease III (Exo III)-catalyzed release
of a Zn2+-dependent ligation DNAzyme with the DNAzyme-driven
strand displacement reaction (SDR) to develop a novel homogeneous
colorimetric bioassay method for kanamycin (Kana) antibiotic detection.
Upon the biorecognition reaction between Kana and a designed hairpin
DNA, the DNAzyme-containing strand can be catalytically released by
Exo III. Then, this DNAzyme will catalyze the ligation of two oligonucleotides
to cause a SDR and the aggregation of gold nanoparticles (Au NPs)
labeled by two linker DNA strands. Due to the aggregation of Au NPs
for colorimetric signal transduction and the Exo III and SDR-assisted
dual signal amplification, this method shows a wide linear range of
5 orders of magnitude and a very low detection limit down to 8.1 fg
mL–1. Together with its excellent selectivity, repeatability,
reliability, and convenient manipulation, the proposed method shows
a great potential for the food quality monitoring application.