用于检测水环境中银离子浓度的荧光适体传感器研究

银凭借其独特的性能,在医疗材料、摄影、电子、成像等行业中应用广泛.然而,银离子被列为最具毒性的重金属离子之一,会对环境以及人类的生命健康造成严重威胁.为了灵敏、特异性的检测水环境中的银离子浓度,利用纳米金的优良光学猝灭性以及双链核酸适体捕获银离子能力更强的优点,结合荧光能量共振转移原理,提出一种用于检测水环境中银离子浓...

A Fluorescence Aptasensor for Detecting Silver Ion Concentration inAqueous Environment

Silver is widely used in medical materials,photography,electronics,imaging and other industries because of its unique properties.However,silver ions are listed as one of the most toxic heavy metal ions,which poses a serious threat to the environment and human health.In order to detect the concentration of silver ions in an aqueous environment sensitively and accurately,a fluorescence aptasensor for detecting the concentration of silver ions in aqueous environment is proposed,which takes advantage of the excellent optical quenching property of nanogold and the stronger ability of double chain aptamers to capture silver ions based on the principle of fluorescence energy resonance transfer.Aptamer modified with SH bonds were mixed with nanogold to form stable nanostructures,and aptamer labeled with FAM were added to form a working solution to detect the concentration of silver ions.In the absence of silvers,two aptamers cannot hybridize with each other due to the repulsive force between the mismatched bases C—C,and the reaction system has strong fluorescence.In the presence of silver ions,the mismatched C—C in the double-stranded aptamers can form a stable C—Ag⁺—C base pair with the silver ions through the interaction between metal ion and base.The generation of this composite structure will shorten the distance between the gold nanoparticles and the fluorophore,so that the fluorescence signal will gradually weaken with the increase of silver ion concentration.According to the change of fluorescence intensity before and after adding silver ion,the concentration of silver ion can be detected.At the same time,in order to improve the sensitivity and stability of the sensor,the concentration ratio of gold and nucleic acid aptamers in the working solution,the concentration of sodium chloride,the pH of the buffer and the culture temperature were optimized.The results showed that when the volume ratio of 0.0125 g·L^-1nano gold to 5μmol·L^-1aptamer was 5∶1,the concentration of NaCl was 260 mmol·L^-1,the pH of the buffer was 7,and the culture temperature was 30℃,the initial fluorescence intensity of the working solution was the strongest,the detection limit of silver ion was 10 nmol·L^-1,and the correlation coefficient was R^( 2)=0.99.Based on the characteristics of high recognition ability and strong affinity of aptamers to silver ions,the sensor showed good selectivity to silver ions and was not disturbed by other substances.In addition,the sensor has good specificity for silver ion concentration detection,and has the advantages of simple operation,sensitivity and no introduction of toxic solvents,so it has a good application prospect for silver ion concentration detection in the water environment.