title: A novel M-shape electrochemical aptasensor for ultrasensitive detection of tetracyclines.
abstract: Analytical techniques for detection and quantitation of tetracyclines in food products are greatly in demand. In this study, a novel electrochemical aptasensor was designed for ultrasensitive and selective detection of tetracyclines, based on M-shape structure of aptamer (Apt)-complementary strands of aptamer (CSs) complex, exonuclease I (Exo I) and gold electrode. The aptasensor was developed to make a noticeable electrochemical difference in the absence and presence of tetracycline. In the absence of tetracycline, the M-shape structure, which acts as a gate and barrier for the access of redox probe to the surface of gold electrode remains intact, leading to a weak electrochemical signal. Upon addition of tetracycline, Apt leaves CSs, resulting in disassembly of M-shape structure and following the addition of Exo I, a strong electrochemical signal was observed. The developed analytical assay indicated high selectivity toward tetracycline with a limit of detection (LOD) as low as 450 pM. Moreover, the designed aptasensor was effectively used for the detection of tetracycline in milk and serum samples with LODs of 740 and 710 pM, respectively.
authors.affiliation: Targeted Drug Delivery Research Center, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran.
authors.forename: Seyed Mohammad
authors.initials: SM
authors.lastname: Taghdisi
authors.affiliation: Nanotechnology Research Center, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran; Research Institute of Sciences and New Technology, Mashhad, Iran.
authors.forename: Noor Mohammad
authors.initials: NM
authors.lastname: Danesh
authors.affiliation: Nanotechnology Research Center, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Ramezani
authors.affiliation: Pharmaceutical Research Center, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran. Electronic address: abnouskh@mums.ac.ir.
authors.forename: Khalil
authors.initials: K
authors.lastname: Abnous
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000032:analysis* / Q000097:blood*; D052157:Aptamers, Nucleotide / Q000737:chemistry*; D015374:Biosensing Techniques / Q000379:methods*; D055664:Electrochemical Techniques / Q000379:methods; D004566:Electrodes; D005090:Exodeoxyribonucleases / Q000737:chemistry; D005504:Food Analysis / Q000379:methods; D006046:Gold / Q000737:chemistry; D006801:Humans; D057230:Limit of Detection; D008892:Milk / Q000737:chemistry*; D013754:Tetracyclines / Q000032:analysis* / Q000097:blood*
chemical_list: D000900:Anti-Bacterial Agents; D052157:Aptamers, Nucleotide; D013754:Tetracyclines; D006046:Gold; D005090:Exodeoxyribonucleases; C028450:exodeoxyribonuclease I
keywords: Electrochemical aptasensor; Exonuclease I; M-shape structure; Tetracyclines