title: Highly sensitive impedimetric aptasensor based on covalent binding of gold nanoparticles on reduced graphene oxide with good dispersity and high density.
abstract: A series of gold nanoparticles (AuNPs) that were covalently bound to 2-aminothiophenol-functionalized reduced graphene oxide (Au-ATP-rGO) composites have been synthesized with well-dispersed and controllable surface coverage of AuNPs. Aptamer immobilization capacity studies demonstrated that the surface density of AuNPs played a key role in increasing the amount of anchoring aptamers to enhance the sensitivity of affinity based detection. With the composites possessing dense surface coverage of AuNPs as a versatile signal amplified platform, a label-free aptasensor for the sensitive and selective detection of small molecules (ochratoxin A in this case) has been developed using electrochemical impedance spectroscopy (EIS). A wide linear range of 0.1-200 ng mL(-1) was obtained with a low detection limit of 0.03 ng mL(-1) (S/N = 3). This work provides a universal strategy for the sensitive detection of a variety of targets in a truly label-free manner by means of changing the corresponding aptamer. The promising platform based on the combination of Au-ATP-rGO composites, EIS technique, and aptamers would have great potential applications in clinical diagnosis, environmental analysis, and food safety monitoring.
authors.affiliation: Key Laboratory of Modern Agriculture Equipment and Technology, School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang, 212013, P. R. China. wangkun@ujs.edu.cn.
authors.forename: Jing
authors.initials: J
authors.lastname: Qian
authors.forename: Ling
authors.initials: L
authors.lastname: Jiang
authors.forename: Xingwang
authors.initials: X
authors.lastname: Yang
authors.forename: Yuting
authors.initials: Y
authors.lastname: Yan
authors.forename: Hanping
authors.initials: H
authors.lastname: Mao
authors.forename: Kun
authors.initials: K
authors.lastname: Wang
mesh_terms: D052157:Aptamers, Nucleotide / Q000737:chemistry*; D058266:Dielectric Spectroscopy; D006046:Gold / Q000737:chemistry*; D006108:Graphite / Q000737:chemistry*; D057230:Limit of Detection; D053768:Metal Nanoparticles; D046529:Microscopy, Electron, Transmission; D010084:Oxidation-Reduction; D010087:Oxides / Q000737:chemistry; D013056:Spectrophotometry, Ultraviolet; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D052157:Aptamers, Nucleotide; D010087:Oxides; D006046:Gold; D006108:Graphite