DNAzyme-powered DNA walking machine for ultrasensitive fluorescence aptasensing of kanamycin

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ORIGINAL PAPER

DNAzyme-powered DNA walking machine for ultrasensitive fluorescence aptasensing of kanamycin Zongqi Yang 1 & Mei Liu 1

&

Baoxin Li 2

Received: 14 May 2020 / Accepted: 6 November 2020 # Springer-Verlag GmbH Austria, part of Springer Nature 2020

Abstract A DNAzyme-powered DNA walking machine was constructed to develop the fluorescence aptasensing for sensitive detection of kanamycin. The aptamer for kanamycin is partially hybridized with complementary DNA (cDNA) modified on magnetic beads (MBs). The specific interaction of target and aptamer triggered the cDNA to be free tentatively, which captured walker DNA. Then the autonomous motion of DNA walker on MBs surface was propelled via DNAzyme digestion of recognition sites. The signal probe was separated, and the amplified fluorescence signal was achieved by the accumulation of the signal probe. Kanamycin was used as a model analyte, and the developed assay achieves a detection limit of 0.00039 ng·mL−1 (S/N = 3) within a linear detection range from 0.001 to 2000 ng·mL−1. This aptasensing strategy can be extended for detection of other antibiotics by adapting corresponding target recognition aptamer sequence. Keywords Kanamycin . Aptamer . DNA walker machine . Fluorescence detection

Introduction Kanamycin, one of the aminoglycoside antibiotics, has a certain antibacterial effect on some Gram-negative and Grampositive bacteria [1]. However, irrational and inappropriate use of kanamycin leads to residue in animal-derived foods. The kanamycin residues can cause serious adverse effects and endanger human health with potential harm to public health and environment [2–4]. The maximum residue limit of kanamycin in milk has been implemented by different countries, for example, 150 μg/kg in the EU and 200 μg/kg in China [5, 6]. Therefore, it critically needs to develop sensitive, rapid, and accurate sensing platform for monitoring residues of kanamycin in animal-derived foods [5].

* Mei Liu [email protected] 1

Key Laboratory of Analytical Chemistry for Life Science of Shaanxi Province and Engineering Research Center of High Value Utilization of Western China Fruit Resources, College of Food Engineering and Nutritional Science, Shaanxi Normal University, Xi’an 710119, China

2

Key Laboratory of Analytical Chemistry for Life Science of Shaanxi Province, School of Chemistry & Chemical Engineering, Shaanxi Normal University, Xi’an 710119, China

Until now, a variety of analytical methods for quantification of kanamycin have been developed including chromatography [7], high-performance liquid chromatography [8], electrochemical method [9], and enzyme-linked immunosorbent assay [10]. Despite their satisfactory accuracy and sensitivity, some imperfectness are involved in above detection techniques, such as time-consuming operation and difficulty in the preparation of antibodies for small molecules. Aptamers are artificial single-stranded oligonucleotides that exhibit distinct advantages of special recognition ability, high affinity to targets, synthetic amenabi