A competitive colorimetric aptasensor for simple and sensitive detection of kanamycin based on terminal deoxynucleotidyl transferase-mediated signal amplification strategy. (30th May 2022)

• Record Type: Journal Article
• Authors: Zhao, Tingting; Chen, Qian; Wen, Yanli; Bian, Xiaojun; Tao, Qing; Liu, Gang; Yan, Juan
• Is Part Of: Food chemistry. Volume 377(2022)
• Publication Date: 2022-05-30
• Subjects: Aptamer -- Biosensor -- Signal amplification strategy -- Magnetic beads -- Antibiotic residues -- Food safety; Food -- Analysis -- Periodicals; Food -- Composition -- Periodicals; 664
• DOI: 10.1016/j.foodchem.2022.132072
• Languages: English
• ISSNs: 0308-8146

Abstract

Graphical abstract: Highlights: Integration of TdTase-mediated signal amplification technique and colorimetry. MBs serve for rapid magnetic separation of the captured target from sample matrix. Desirable detection sensitivity (9 pM) and specificity for kanamycin standard. Simple, highly sensitive and suitable for on-site food safety screening. Abstract: We developed a rapid and sensitive colorimetric biosensor based on competitive recognition between kanamycin (KAN), magnetic beads-kanamycin (MBs-KAN) and aptamer and terminal deoxynucleotidyl transferase (TdT)-mediated signal amplification strategy. In the absence of KAN, aptamers recognize MBs-KAN. TdT can amplify oligonucleotides to the 3′-OH ends of aptamers, with biotin-dUTP being embedded in the long single stranded DNA (ssDNA). Then the assay produced visual readout due to the horseradish peroxidase (HRP)-catalyzed color change of the substrate after the linkage between biotin and streptavidin (SA)-HRP. In the presence of KAN, however, aptamers tend to bind free KAN rather than MBs-KAN. In this case, aptamers are isolated by magnetic separation, resulting in the failure of signal amplification and catalytic signals. This competitive colorimetric sensor showed excellent selectivity toward KAN with the limit of detection (LOD) as low as 9 pM. And recovery values were between 93.8 and 107.8% when spiked KAN in milk and honey samples.