Ma Dandan,Yuan Yali,Xiao Xilin,Gao Yangyang,Li Yuhui,Xu Wenhui,Long Wei
A novel and highly sensitive electrochemical DNAzymes biosensor was fabricated using Au nanoparticles (AuNPs) immobilized on the surface of Au electrode that had been previously modified with self-assembled monolayers of 1,6-hexanedithiol. Different modified electrodes were prepared and characterized by cyclic voltammetry and electrochemical impedance spectroscopy. The AuNPs were found to have a large surface area to anchor a large number of negatively charged phosphate backbones of DNAzymes, which further absorbed the electroactive indicator of hexaammineruthenium(III) ([Ru(NH 3 ) 6 ] 3+ ) to amplify the electrochemical signal. In the presence of target molecules, a large amount of DNA partly associated with [Ru(NH 3 ) 6 ] 3+ were removed from the electrode surface, leading to a significant decrease in peak current. Differential pulse voltammetry signals of [Ru(NH 3 ) 6 ] 3+ provided quantitative measures of the concentrations of uranyl ion (UO 2
2+ ), with linear calibration ranging from 13 pM to 0.15 nM and a detection limit of 5 pM. The presence of other metal ions did not affect the detection of UO 2
2+ , which indicated the high specificity of UO 2
2+ . Therefore, a new electrochemical DNAzymes sensor was designed with specific DNAzymes and AuNPs as immobilization platform and signal amplifier.
In order to achieve the on-site rapid detection of trace uranium under excitation with visible light and avoid the harmful effect of toxic organic solvent to human body and organisms, in this work, a novel water-soluble, environmental-friendly and biocompatible aggregation-induced emission (AIE) fluorescence probe was fabricated by introducing the pyridine quaternary ammonium cation and amide group into the propeller structure of triphenylamine (TPA). And by creatively using bovine serum albumin (BSA) in PBS buffer as the sensitizing agent to replace the toxic organic solvent, the probe can emit intense red fluorescence under excitation with visible light (470 nm), exhibiting very low cytotoxicity and great anti-interference ability against large equivalent of different metal ions and anions over wide pH range. After further integration with the self-constructed portable fiber optical sensing system, the satisfying detection limit as low as 7.44 nM (1.77 ppb) can be achieved. The established method has been applied successfully for sensing uranium in complex real samples such as uranium leachate, seawater and cancer cells, demonstrating excellent analytical performance and great potential for in-situ rapid detection and timely evaluation of the uranium contamination in vivo and in field.
危险品化学品经营许可证（带存储）