Application Of Fluorescent Sensors Fof The Detection Of Anthrax Biomarker And Tetracycline

In recent years,pathogenic bacteria infection and antibiotic abuse have become major livelihood issues concerning human life and health and social stability.The development of portable,sensitive and economical methods for the detection of pathogenic bacteria and antibiotic is of great importance.Fluorescence sensor-based detection methods have attracted wide attention from researchers due to their strong specificity,high cost effectiveness,and ability to become miniaturized point-of-care testing（POCT）devices.In this paper,two portable ratio fluorescence sensors were developed for the detection of anthrax biomarkers and tetracycline in environmental and food samples respectively,which not only opens up a new avenue for green synthesis of efficient fluorescent sensors,but also provides an effective sensing strategy for environmental monitoring,food safety and disease diagnosis.Specific work is as follows:1.The development of sensitive and selective methods for the detection of anthrax biomarkers-2,6 Dipicolinic acid（DPA）is important for the protection of human life and health and food safety.An Eu³⁺coupled carbon nitride（g-C₃N₄）nanosheet fluorescence sensor was constructed for the selective detection of DPA.In the presence of analyte DPA,the blue fluorescence of g-C₃N₄ as a reference signal remains unchanged,and DPA will combine with Eu³⁺on the sensor to generate antenna effect,making it emit red fluorescence as a response signal,with the detection limit as low as 13 nmol/L,which is significantly lower than the maximum residual level of bacterial spore biomarkers for human infection（60μmol/L）.In addition,a portable smartphone-assisted point-of-care detection platform without the need for large and expensive instruments has been developed.This smart sensing platform has been successfully applied to the visual detection of DPA in actual tap water and orange juice sample with good standard addition recovery（84.20%-93.13%）,demonstrating the good sensitivity and reliability of the sensor for DPA detection.This novel sensing method provides an economical,sensitive and portable sensing strategy for the detection of biomarkers.2.Tetracycline（TC）is one of the most commonly used antibiotics,and its abuse in animal husbandry or clinical treatment has caused serious threats to food safety and ecological environment.A ratio fluorescence sensor with Eu³⁺coupled copper nanoclusters（Cu NCs）was developed for the highly sensitive detection of tetracycline.Tetracycline can quench the green fluorescence of copper clusters by internal filtration effect,while also enhancing the red fluorescence of Eu³⁺by antenna effect.The two fluorescence signals change inversely.The detection limit of TC was as low as 8.6 nmol/L,which was lower than the maximum residual amount of TC in food stipulated by the European Union（225nmol/L）,and it was applied to the detection of TC in tap water and milk samples,and the standard recovery rate was 89.3%-93.6%.Based on the above sensors,a rapid detection platform assisted by test strips and smart phones was developed for visual detection of TC,which greatly reduced detection cost and detection time.In addition,an advanced logic gate platform is constructed to reflect the concentration level of TC through a simple computer language,which provides a new perspective for monitoring TC with intelligent analysis equipment.