title: Nitrogen-Doped Graphene Quantum Dots@SiO2 Nanoparticles as Electrochemiluminescence and Fluorescence Signal Indicators for Magnetically Controlled Aptasensor with Dual Detection Channels.
abstract: We proposed a facile method to prepare the nitrogen-doped graphene quantum dots (NGQDs) doped silica (NGQDs@SiO2) nanoparticles (NPs). The NGQDs@SiO2 NPs were further explored as a versatile signal indicator for ochratoxin A (OTA) aptasensing by combination with electrochemiluminescence (ECL) and fluorescence (FL) detection. In this strategy, the core-shell Fe3O4@Au magnetic beads (MBs) acted as a nanocarrier to immobilize the thiolated aptamer specific for OTA, and the amino modified capture DNA (cDNA) was efficiently tagged with NGQDs@SiO2 NPs. The multifunctional aptasensor was thus fabricated by assembly of the NGQDs@SiO2 NPs onto the surface of Fe3O4@Au MBs through the high specific DNA hybridization between aptamer and cDNA. Upon OTA incubation, the aptamer linked with Fe3O4@Au MBs preferred to form an aptamer-OTA complex, which resulted in the partial release of the preloaded NGQDs@SiO2 NPs. The more OTA molecules in the detection system, the more NGQDs@SiO2 NPs were released into the bulk solution and the less preloaded NGQDs@SiO2 NPs were accumulated on the magnetic electrode surface. This provided a dual channel for OTA detection by combination with the enriched solid-state ECL and homogeneous FL detection. The FL assay exhibits a wide dynamic range and is more reproducible due to the homogeneous detection while the ECL assay possesses a lower detection limit and is preferable by using a cheaper instrument. One can obtain a preliminary screen from FL assay and a more accurate result from ECL assay. Integrating the virtues of dual analytical modality, this aptasensing strategy well-balanced the rapidity, sensitivity, and dynamic range, making it promising to other targets with aptamer sequences.
authors.affiliation: School of Food and Biological Engineering and ‡Key Laboratory of Modern Agriculture Equipment and Technology, School of Chemistry and Chemical Engineering, Jiangsu University , Zhenjiang 212013, People's Republic of China.
authors.forename: Chengquan
authors.initials: C
authors.lastname: Wang
authors.affiliation: School of Food and Biological Engineering and ‡Key Laboratory of Modern Agriculture Equipment and Technology, School of Chemistry and Chemical Engineering, Jiangsu University , Zhenjiang 212013, People's Republic of China.
authors.forename: Jing
authors.initials: J
authors.lastname: Qian
authors.affiliation: School of Food and Biological Engineering and ‡Key Laboratory of Modern Agriculture Equipment and Technology, School of Chemistry and Chemical Engineering, Jiangsu University , Zhenjiang 212013, People's Republic of China.
authors.forename: Kun
authors.initials: K
authors.lastname: Wang
authors.affiliation: School of Food and Biological Engineering and ‡Key Laboratory of Modern Agriculture Equipment and Technology, School of Chemistry and Chemical Engineering, Jiangsu University , Zhenjiang 212013, People's Republic of China.
authors.forename: Mengjuan
authors.initials: M
authors.lastname: Hua
authors.affiliation: School of Food and Biological Engineering and ‡Key Laboratory of Modern Agriculture Equipment and Technology, School of Chemistry and Chemical Engineering, Jiangsu University , Zhenjiang 212013, People's Republic of China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Liu
authors.affiliation: School of Food and Biological Engineering and ‡Key Laboratory of Modern Agriculture Equipment and Technology, School of Chemistry and Chemical Engineering, Jiangsu University , Zhenjiang 212013, People's Republic of China.
authors.forename: Nan
authors.initials: N
authors.lastname: Hao
authors.affiliation: School of Food and Biological Engineering and ‡Key Laboratory of Modern Agriculture Equipment and Technology, School of Chemistry and Chemical Engineering, Jiangsu University , Zhenjiang 212013, People's Republic of China.
authors.forename: Tianyan
authors.initials: T
authors.lastname: You
authors.affiliation: School of Food and Biological Engineering and ‡Key Laboratory of Modern Agriculture Equipment and Technology, School of Chemistry and Chemical Engineering, Jiangsu University , Zhenjiang 212013, People's Republic of China.
authors.forename: Xingyi
authors.initials: X
authors.lastname: Huang
mesh_terms: D052157:Aptamers, Nucleotide / Q000737:chemistry*; D015374:Biosensing Techniques; D058266:Dielectric Spectroscopy; D055664:Electrochemical Techniques / Q000379:methods*; D006108:Graphite / Q000737:chemistry*; D008163:Luminescent Measurements / Q000379:methods*; D008280:Magnetics; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D009584:Nitrogen / Q000737:chemistry*; D009793:Ochratoxins; D045663:Quantum Dots / Q000737:chemistry* / Q000648:ultrastructure; D012822:Silicon Dioxide / Q000737:chemistry*; D013050:Spectrometry, Fluorescence; D013696:Temperature; D013997:Time Factors
chemical_list: D052157:Aptamers, Nucleotide; D009793:Ochratoxins; C025589:ochratoxin A; D012822:Silicon Dioxide; D006108:Graphite; D009584:Nitrogen
keywords: aptasensor; electrochemiluminescence; fluorescence; nitrogen-doped graphene quantum dots; ochratoxin A; silica