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Published on: June 24, 2019
A robust tag-free aptasensor for fluorescent detection of kanamycin assisted by signal intensification potency of
Zahra Sirousi1, Zahra Khoshbin1, Mohammad Ramezani2
1Targeted Drug Delivery Research Center, Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Mashhad, Iran; Pharmaceutical Research Center, Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Mashhad, Iran; Department of Medicinal Chemistry, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran.
Abstract:
Rolling circle amplification (RCA) process as an excellent DNA amplifier strategy possesses the merits of high performance and easy operation. In this research, a sensitive RCA-based fluorescent aptasensor was fabricated for the detection of kanamycin residues in food. The aptasensing approach consisted of two main steps; immobilization of biotinylated kanamycin aptamer on streptavidin magnetic beads (SMB) and separation of free complementary strands (CS) from the SMB-aptamer/kanamycin at the first step. For the second step, RCA procedure was applied as signal magnifier and SYBR Green was added as fluorescent indicator dye. The linear relation between the aptasensor response and kanamycin concentration was obtained from 5 nM to 100 nM with the detection limit of 1.93 nM (S/N = 3). The aptasensor displayed satisfactory selectivity among other antibiotics. The developed aptasensor is reliable for monitoring kanamycin in milk as a common foodstuff.

