title: A triple-amplification colorimetric assay for antibiotics based on magnetic aptamer-enzyme co-immobilized platinum nanoprobes and exonuclease-assisted target recycling.
abstract: Herein, an ultrasensitive and selective colorimetric assay for antibiotics, using chloramphenicol (CAP) as the model analyte, was developed based on magnetic aptamer-HRP-platinum composite probes and exonuclease-assisted target recycling. The composite probes were prepared through immunoreactions between the double stranded DNA antibody (anti-DNA) labeled on core-shell Fe3O4@Au nanoparticles (AuMNP-anti-DNA) as the capture probe, and the double stranded aptamer (aptamer hybrid with its complementary oligonucleotides) labeled on Pt@HRP nanoparticles as the nanotracer (ds-Apt-HRP-PtNPs). When the CAP samples were incubated with the probes for 30 min at room temperature, they could be captured by the aptamer to form a nanotracer-CAP complex, which was then released into the supernatant after magnetic separation. This is because the anti-DNA on the capture probes cannot recognize the single strand aptamer-CAP complex. The exonuclease I (Exo I) added into the supernatant can further digest the aptamer-CAP from the 3'-end of the aptamer and the CAP in the aptamer-CAP complex can be released again, which can further participate in a new cycling process to react with the probes. Pt and HRP in the nanotracer could both catalyze and dual amplify the absorbance at 650 nm ascribed to the 3,3',5,5'-tetramethylbenzidine (TMB)-H2O2 system. Moreover, Exo I can assist the target recycling, which can further amplify the signal. Thus, the triple amplified signal can be quantified by ultraviolet-visible spectroscopy. The experimental results showed that the CAP detection possessed a linear range of 0.001-10 ng mL(-1) and a detection limit of 0.0003 ng mL(-1) (S/N = 3). The assay was successfully employed to detect CAP in milk, which is much more facile, time saving, and sensitive than the commercial ELISA kits.
authors.affiliation: Faculty of Material Science and Chemical Engineering, Ningbo University, Ningbo, 315211, China.
authors.forename: Yangbao
authors.initials: Y
authors.lastname: Miao
authors.affiliation: Faculty of Material Science and Chemical Engineering, Ningbo University, Ningbo, 315211, China.
authors.forename: Ning
authors.initials: N
authors.lastname: Gan
authors.affiliation: Key Laboratory of Asymmetric Synthesis and Chirotechnology of Sichuan Province, Chengdu Institute of Organic Chemistry, Chinese Academy of Sciences, Chengdu, 610041, China.
authors.forename: Hong-Xia
authors.initials: HX
authors.lastname: Ren
authors.affiliation: Faculty of Material Science and Chemical Engineering, Ningbo University, Ningbo, 315211, China.
authors.forename: Tianhua
authors.initials: T
authors.lastname: Li
authors.affiliation: Faculty of Material Science and Chemical Engineering, Ningbo University, Ningbo, 315211, China.
authors.forename: Yuting
authors.initials: Y
authors.lastname: Cao
authors.affiliation: Faculty of Material Science and Chemical Engineering, Ningbo University, Ningbo, 315211, China.
authors.forename: Futao
authors.initials: F
authors.lastname: Hu
authors.affiliation: Faculty of Material Science and Chemical Engineering, Ningbo University, Ningbo, 315211, China.
authors.forename: Zhongdan
authors.initials: Z
authors.lastname: Yan
authors.affiliation: Faculty of Food Science and Engineering, Nanjing University of Finance and Economics, Nanjing, 210000, China.
authors.forename: Yinji
authors.initials: Y
authors.lastname: Chen
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000032:analysis* / Q000378:metabolism; D052157:Aptamers, Nucleotide / Q000737:chemistry* / Q000378:metabolism; D001560:Benzidines / Q000737:chemistry; D015374:Biosensing Techniques / Q000379:methods*; D002701:Chloramphenicol / Q000032:analysis* / Q000378:metabolism; D003124:Colorimetry / Q000379:methods; D005090:Exodeoxyribonucleases / Q000378:metabolism; D006046:Gold / Q000737:chemistry; D006861:Hydrogen Peroxide / Q000737:chemistry; D057230:Limit of Detection; D058185:Magnetite Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D008892:Milk / Q000737:chemistry*; D010984:Platinum / Q000737:chemistry*
chemical_list: D000900:Anti-Bacterial Agents; D052157:Aptamers, Nucleotide; D001560:Benzidines; D058185:Magnetite Nanoparticles; C021758:3,3',5,5'-tetramethylbenzidine; D010984:Platinum; D002701:Chloramphenicol; D006046:Gold; D006861:Hydrogen Peroxide; D005090:Exodeoxyribonucleases; C028450:exodeoxyribonuclease I