A Label-free and Functional Fluorescent Oligonucleotide Probe Based on a G-Quadruplex Molecular Beacon for the Detection of Kanamycin

• DOI: 10.1007/s40242-018-7366-0
• Publication Date: 2018-07-06T23:38:24Z
• Authors: Yuqing Zhu; Wei Li; Suzhen Tan; Tianxiao Chen
• Keywords: Kanamycin; Molecular beacon; Aptamer; Thioflavin

A label-free and turn-off fluorescent method for the quantitative detection of kanamycin based on a functional molecular beacon was developed. The molecular beacon consists of two hairpin structures with a split G-rich oligonucleotide in the middle. The kanamycin’s aptamer formed the loops portion for recognizing kanamycin, and the G-quadruplex bound by Thioflavin T(ThT) was employed as the reporter. In the absence of target, the molecular beacon folded into double stem-loops and the splited G-rich oligonucleotid came close to form a G-quadruplex. When ThT bound to the G-quadruplex, the fluorescence intensity of the solution increased. Upon the addition of kanamycin, the function between kanamycin and aptamer unfolded the hairpin and disassembled the G-quadraplex structure, resulting in a significant decrease in the fluorescence intensity. A good linear relationship ranging from 0.7 nmol/L to 10 nmol/L was achieved and the limit of detection was 0.37 nmol/L. Besides, it could efficiently recognize kanamycin in real samples.