Research On A New Method For Detection Of Mycotoxins And Metal Ions Based On Aggregation-Induced Emission

Food safety is a global public health and safety issue.In recent years,food safety incidents have become more frequent and food safety issues have gradually become a focus of social concern.Globally,the problems and diseases caused by food safety not only cause serious economic losses,but also seriously endanger people's livelihood.Therefore,researching a rapid and accurate food safety detecting method is conducive to the prevention and control of food safety incidents.It has important practical significance and social value.Aptamers are widely used in the field of food safety detection due to their good specificity,wide target range and flexibility of biochemical modification.In the field of food safety testing,toxins produced by food spoilage and heavy metal residues are important indicators of food safety hazards.Based on this,in this thesis,the work focused on the application of fluorescent probe and aptamer recognition based on aggregation-induced emission for the detection of aflatoxin B1 and heavy metal silver ions.Based on fluorescence resonance energy transfer technology,such a rapid,sensitive and reliable new method provided new ideas for enriching and improving food safety technology.First,the application of 9,10-distyrylsulfonium quaternary ammonium salt?DSAI?biosensor probes with aptamer recognition technology and fluorescence resonance energy transfer technology in the detection of aflatoxin B₁ was studied.Using DSAI as fluorescent probe,aptamer as recognition molecule,and MoS₂ nanosheet as quenching material,In the presence of the target,the aptamer combines with the target and form a complex through specific binding,resulting in the release of the aptamer from MoS₂ nanosheet during which the DSAI detached from the MoS₂along with the aptamer.In this work,DSAI and aptamer were combined by electrostatic adsorption and hydrophobic interaction.Using aflatoxin B₁ as an analyte,a fluorescent aptamer sensor based on aggregation-induced emission was constructed.The detection range was from0.01 ng/mL to 500 ng/mL with a detection limit of 0.001 ng/mL.Second,the application of 9,10-distyrylsulfonium quaternary ammonium salt?DSAI?biosensor probes with aptamer recognition technology and fluorescence resonance energy transfer technology in the detection of heavy metal silver ions was studied.Using DSAI as a fluorescent probe,aptamers as recognition molecules,and BP nanosheets as quenching materials,in the presence of the target,the DSAI attached aptamer form a U-shaped structure through specific binding resulting in the release of the aptamer from the BP.The aptamer combines with the target and form a complex through specific binding,resulting in the release of the aptamer from BP nanosheet during which the DSAI detached from the BP along with the aptamer.In this work,DSAI and aptamer were combined by electrostatic adsorption and hydrophobic interaction.Using silver ions as an analyte,a fluorescent aptamer sensor based on aggregation-induced emission was constructed.The detection range was from 0.01 ng/m L to 100 ng/m L with a detection limit of0.002 ng/mL.