Development Of A Novel Mercury Ion Highly Sensitive Biosensor Based On Aptamer

The phenomenon of heavy metal pollution is widespread in every place,including soil and water,which has aroused great concern in the society.Therefore,the detection of trace heavy metals has become a research hotspot in this field.In this paper,several biosensors for detecting heavy metals have been developed based on the conductivity of nanogold and the high immunity of aptamers.The biosensor not only has simple preparation,high sensitivity,high precision,but also has high anti-interference,and has achieved good results in the detection of heavy metals in water.Chapter 1:Outlines the hazards and current research status of heavy metals,summarizes the properties of aptamers and the application of aptamer biosensors,alone with the basis for this study and the main research content.Chapter 2:AuNPs-aptamer complexes are prepared by Au-S bond formation with intermediate hexadinonanol to modify the surface of the electrode,constructing a new type of AuNPs-aptamer High-sensitivity sensors that are used to directly detect mercury ions.The experimental results show that the biosensor exhibits good linearity,good repeatability,and selectivity when detecting heavy-metal mercury,and it is present at low concentrations(0.005-5 ppb)and high concentrations(0.5-20 ppb)with the lowest detection limit of 1.110?10-3ppb.The recovery of Hg(?)from tap water and lake water in actual samples is between 95.4%-115.9%.Chapter 3:A novel material nanogold wire electrode is prepared,construting a new type of nano-biosensor by forming Au-S bonds between the fluorenyl group on the aptamer and gold nanowires,and the detection of trace mercury is realized.The results show that the biosensor has high selectivity and high sensitivity for mercury ion detection.In addition,good linearity was observed at low concentration(0.0005-0.2 ppb)and high concentration(0.04-4 ppb)with the lowest detection limit of 4.333*10-5 ppb,and satisfactory results were obtained.Chapter 4:Nano-AuNPs-ssDNA complexes are prepared.AuNPs-ssDNA complexes were modified to the surface of glassy carbon electrodes by Au-S bonds through gold plating after electrodeposition.A novel highly sensitive sensor based on nanogold-double stranded aptamer was developed and applied to the detection of mercury ions.It shows good linearity,high sensitivity and selectivity when detecting heavy metal mercury,and it shows good linearity at low concentrations(0.005-5 ppb)and high concentrations(0.5-10 ppb)with the lowest detection limit of 1.714*10-3 ppb.The biosensor was applied to spike the actual sample,and the recovery rate was between 94.1%-110%.