title: Colorimetric aptasensing of ochratoxin A using Au@Fe3O4 nanoparticles as signal indicator and magnetic separator.
abstract: Gold nanoparticles (Au NPs) doped Fe3O4 (Au@Fe3O4) NPs have been synthesized by a facile one-step solvothermal method. The peroxidase-like activity of Au@Fe3O4 NPs was effectively enhanced due to the synergistic effect between the Fe3O4 NPs and Au NPs. On this basis, an efficient colorimetric aptasensor has been developed using the intrinsic dual functionality of the Au@Fe3O4 NPs as signal indicator and magnetic separator. Initially, the amino-modified aptamer specific for a typical mycotoxin, ochratoxin A (OTA), was surface confined on the amino-terminated glass beads surafce using glutaraldehyde as a linker. Subsequently, the amino-modified capture DNA (cDNA) was labeled with the amino-functionalized Au@Fe3O4 NPs and the aptasensor was thus fabricated through the hybridization reaction between cDNA and the aptamers. While upon OTA addition, aptamers preferred to form the OTA-aptamer complex and the Au@Fe3O4 NPs linked on the cDNA were released into the bulk solution. Through a simple magnetic separation, the collected Au@Fe3O4 NPs can produce a blue colored solution in the presence of 3,3',5,5'-tetramethylbenzidine and H2O2. When the reaction was terminated by addition of H(+) ions, the blue product could be changed into a yellow one with higher absorption intensity. This colorimetric aptasensor can detect as low as 30 pgmL(-1) OTA with high specificity. To the best of our knowledge, the present colorimetric aptasensor is the first attempt to use the peroxidase-like activity of nanomaterial for OTA detection, which may provide an acttractive path toward routine quality control of food safety.
authors.affiliation: School of Food and Biological Engineering, Jiangsu University, Zhenjiang 212013, PR China.
authors.forename: Chengquan
authors.initials: C
authors.lastname: Wang
authors.affiliation: Key Laboratory of Modern Agriculture Equipment and Technology, School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013, PR China.
authors.forename: Jing
authors.initials: J
authors.lastname: Qian
authors.affiliation: Key Laboratory of Modern Agriculture Equipment and Technology, School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013, PR China. Electronic address: wangkun@ujs.edu.cn.
authors.forename: Kun
authors.initials: K
authors.lastname: Wang
authors.affiliation: Key Laboratory of Modern Agriculture Equipment and Technology, School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013, PR China.
authors.forename: Xingwang
authors.initials: X
authors.lastname: Yang
authors.affiliation: Key Laboratory of Modern Agriculture Equipment and Technology, School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013, PR China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Liu
authors.affiliation: Key Laboratory of Modern Agriculture Equipment and Technology, School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013, PR China.
authors.forename: Nan
authors.initials: N
authors.lastname: Hao
authors.affiliation: School of Food and Biological Engineering, Jiangsu University, Zhenjiang 212013, PR China.
authors.forename: Chengke
authors.initials: C
authors.lastname: Wang
authors.affiliation: Key Laboratory of Modern Agriculture Equipment and Technology, School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013, PR China.
authors.forename: Xiaoya
authors.initials: X
authors.lastname: Dong
authors.affiliation: School of Food and Biological Engineering, Jiangsu University, Zhenjiang 212013, PR China. Electronic address: h_xingyi@163.com.
authors.forename: Xingyi
authors.initials: X
authors.lastname: Huang
mesh_terms: D052157:Aptamers, Nucleotide / Q000737:chemistry*; D015374:Biosensing Techniques / Q000295:instrumentation; D003124:Colorimetry / Q000295:instrumentation*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005504:Food Analysis / Q000295:instrumentation; D005506:Food Contamination / Q000032:analysis; D006046:Gold / Q000737:chemistry*; D018189:Immunomagnetic Separation / Q000295:instrumentation*; D008280:Magnetics / Q000295:instrumentation; D058185:Magnetite Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D009793:Ochratoxins / Q000032:analysis* / Q000737:chemistry / Q000302:isolation & purification
chemical_list: D052157:Aptamers, Nucleotide; D058185:Magnetite Nanoparticles; D009793:Ochratoxins; C025589:ochratoxin A; D006046:Gold
keywords: Au@Fe(3)O(4) nanoparticles; Colorimetric aptasensor; Magnetic separation; Ochratoxin A; Peroxidase-like activity