Fluorescence Sensing Of Acetamiprid In Food Based On Two-dimensional MOF Materials

The problem of pesticide residues in food has always been the focus of food safety.Trace amounts of pesticide residues produced by improper use lead to contamination of food and water sources.After eating related products,it will accumulate in the body and cause harm to human health.In recent years,a variety of new pesticides have been developed and applied,but their rapid detection methods need to be improved.With the development of new technology,a novel detection method integrated with sample pretreatment is urgently needed.Two dimensional metal organic framework（2D MOF）nanosheets not only have the unique properties of 2D materials,but also can possess the excellent adsorption properties and photoelectric conductivity of traditional MOF materials.In recent years,2D MOF nanosheets have attracted extensive attention and have become a new type of important functional nano materials developed by new technologies in the detection field.In this study,an ultra-thin 2D MOF（Cu-TCPP）was synthesized by surfactant assisted method.Take acetamiprid as a represented,a novel rapid and ultrasensitive aptamer biosensing technology was established based on the Cu-TCPP and deoxyribonuclease I（DNase I）assisted fluorescence amplification strategy.As a fluorescence quencher,2D Cu-TCPP nanosheets had exhibited strong adsorption capacity and fluorescence quenching ability for fluorophore-labeled aptamers,which was based on their larger specific surface area and more accessible active sites.The conjugatedπ-electron on the organic ligand TCPP could be combined with the single-stranded DNA（ss DNA）probe throughπ-πstacking interaction,and then the fluorophores labeled on the aptames would be quenched by efficient fluorescence resonance energy transfer（FRET）on the surface of the nanosheets.Based on the difference of affinity between 2D MOF nanosheets for aptamers and aptamer-target complexes,the quantitative detection of target molecules was established.With the increase of the acetamiprid concentration,the fluorescence signal increased gradually.Moreover,DNaseⅠnuclease shows good auxiliary cycle amplification effect on the fluorescence signal of the system,using for further improving the detection sensitivity and the detection time.This proposed strategy had realized the rapid and ultrasensitive detection of acetamiprid with the optimal experimental conditions.The linear detection range was ranged from 0.05 ng·m L^-1 to 5×10³ ng·m L^-1.The limit of the detection was 5.56 pg·m L^-1.The detection time was within 45 min.Due to the specific recognition of the aptamer,the biosensor had also shown good selectivity.The method has been successfully applied to the detection of various food samples and water samples.The recoveries of fruit,vegetable and water samples were 92.37%～109.03%and 95.83%～104.49%,respectively.The strategy had shown a good application prospect.