title: A sensitive electrochemical aptasensor for multiplex antibiotics detection based on high-capacity magnetic hollow porous nanotracers coupling exonuclease-assisted cascade target recycling.
abstract: A multiplex electrochemical aptasensor was developed for simultaneous detection of two antibiotics such as chloramphenicol (CAP) and oxytetracycline (OTC), and high-capacity magnetic hollow porous nanotracers coupling exonuclease-assisted target recycling was used to improve sensitivity. The cascade amplification process consists of the exonuclease-assisted target recycling amplification and metal ions encoded magnetic hollow porous nanoparticles (MHPs) to produce voltammetry signals. Upon the specific recognition of aptamers to targets (CAP and OTC), exonuclease I (Exo I) selectively digested the aptamers which were bound with CAP and OTC, then the released CAP and OTC participated new cycling to produce more single DNA, which can act as trigger strands to hybrid with nanotracers to generate further signal amplification. MHPs were used as carriers to load more amounts of metal ions and coupling with Exo I assisted cascade target recycling can amplify the signal for about 12 folds compared with silica based nanotracers. Owing to the dual signal amplification, the linear range between signals and the concentrations of CAP and OTC were obtained in the range of 0.0005-50 ng mL(-1). The detection limits of CAP and OTC were 0.15 and 0.10 ng mL(-1) (S/N=3) which is more than 2 orders lower than commercial enzyme-linked immunosorbent immunoassay (ELISA) method, respectively. The proposed method was successfully applied to simultaneously detection of CAP and OTC in milk samples. Besides, this aptasensor can be applied to other antibiotics detection by changing the corresponding aptamer. The whole scheme is facile, selective and sensitive enough for antibiotics screening in food safety.
authors.affiliation: State Key Laboratory Base of Novel Functional Materials and Preparation Science, Faculty of Materials Science and Chemical Engineering, Ningbo University, Ningbo 315211, PR China.
authors.forename: Zhongdan
authors.initials: Z
authors.lastname: Yan
authors.affiliation: State Key Laboratory Base of Novel Functional Materials and Preparation Science, Faculty of Materials Science and Chemical Engineering, Ningbo University, Ningbo 315211, PR China. Electronic address: ganning@nbu.edu.cn.
authors.forename: Ning
authors.initials: N
authors.lastname: Gan
authors.affiliation: State Key Laboratory Base of Novel Functional Materials and Preparation Science, Faculty of Materials Science and Chemical Engineering, Ningbo University, Ningbo 315211, PR China.
authors.forename: Tianhua
authors.initials: T
authors.lastname: Li
authors.affiliation: State Key Laboratory Base of Novel Functional Materials and Preparation Science, Faculty of Materials Science and Chemical Engineering, Ningbo University, Ningbo 315211, PR China. Electronic address: caoyuting@nbu.edu.cn.
authors.forename: Yuting
authors.initials: Y
authors.lastname: Cao
authors.affiliation: Nanjing University of Finance and Economics, PR China.
authors.forename: Yinji
authors.initials: Y
authors.lastname: Chen
mesh_terms: D000818:Animals; D052157:Aptamers, Nucleotide / Q000737:chemistry; D015374:Biosensing Techniques / Q000379:methods*; D002417:Cattle; D002701:Chloramphenicol / Q000302:isolation & purification*; D055664:Electrochemical Techniques / Q000379:methods*; D005090:Exodeoxyribonucleases / Q000737:chemistry; D006046:Gold / Q000737:chemistry; D053768:Metal Nanoparticles / Q000737:chemistry; D008892:Milk / Q000737:chemistry; D010118:Oxytetracycline / Q000302:isolation & purification*
chemical_list: D052157:Aptamers, Nucleotide; D002701:Chloramphenicol; D006046:Gold; D005090:Exodeoxyribonucleases; C028450:exodeoxyribonuclease I; D010118:Oxytetracycline
keywords: Chloramphenicol (CAP); Exonuclease I cycling amplification; Magnetic hollow porous nanotracers; Oxytetracycline (OTC); Simultaneous electrochemical determination