Fluorescence Nanobiosensor For Simultaneous And Rapid Detection Of Multiple Veterinary Drugs In Poultry Products

China is one of the biggest poultry producers and consumers.In 2019,China’s poultry production ranked the second in the world and is still developing rapidly.Veterinary drugs are important guarantees for improving poultry production.However,the abuse of veterinary drugs in poultry breeding can easily cause drug residues in poultry products,which poses a threat to human health.Therefore,the safety of poultry products can’t be ignored.In order to ensure the safety of poultry products,the detection method should be efficient,sensitive,high-throughput and convenient,which facilitate in-field monitoring.However,the traditional sample pretreatment method is timeconsuming,complicated with the requirements of volatile and toxic organic reagents.Traditional veterinary drug detection methods such as chromatography require largescale instruments and complicated operation,which limit their in-field application.Rapid detection methods such as immunochromatography are not sensitive enough.In addition,the portability and automation of testing instruments also put forward new requirements for the simplicity of testing methods.To meet requirements of rapid infield monitoring of veterinary drug residues,as well as to avoid the drawbacks of traditional sample pretreatment and detection methods for in-field application,this dissertation proposed a simple pretreatment method,as well as two immunomagnetic bead-and fluorescent quantum dot-based biosensing methods for simultaneous and rapid detection of three veterinary drug residues in poultry products.Furthermore,the detection method was coupled with a portable fluorescence sensing instrument.The main research contents include the following three aspects:(1)In regard to the limitations of conventional pretreatment methods wihich is complex and not suitable for in-field application,Chapter 2 proposed a pretreatment method that can realize rapid and simultaneous extraction of multiple veterinary drug residues in chicken samples.Based on the simple pretreatment process,the effects of various extraction reagents for pretreatment were compared by using immunoassay as evaluation method.As a result,sodium phosphotungstate-magnesium was finally selected as the extraction reagent.Furthermore,the concentration of extraction reagent as well as pretreatment process were optimized.Compared with conventional methods,the proposed pretreatment method can realize the simultaneous extraction of multiple residues without the requirement of organic reagents or large-scale instruments that are difficult to be applied in actual environment.(2)As conventional veterinary drug detection methods are complex and often aim at detecting one single analytes,Chapter 3 proposed a simple and efficient sensing technology that can simultaneously detect three target analytes.Three kinds of antibody modified magnetic beads and three kinds of antigen modified fluorescent quantum dots were synthesized and characterized,respectively.Three kinds of veterinary drugs were captured and seperated by immunomagnetic beads.Also,a competitive immunoassay was established through the competive binding of target veterinary drugs and antigen modified fluorescent quantum dots towards the binding sites on the surface of immunomagnetic beads.The drug concentration was determined by fluorescence signal of antigen modified quantum dots on the magnetic beads surface after magnetic separation.Furthermore,the detection process was optimized.As a result,the sensor realized the quantitative detection of three veterinary drugs in PBS buffer and in chicken breast samples.(3)Concerning the problem that the fluorescent nanobiosensing technology developed in chapter 3 still requires large-scale detection equipment and is difficult to achieve in-field detection,chapter 4 adopted portable fluorescence detector as output device.At the same time,the detection technology suitable for portable detector is proposed.Furthermore,the detection conditions were optimized,and the specificity was investigated.Finally,the detection of three veterinary drugs in chicken extract was successfully achieved,and it could be applied in portable fluorescence detector.The portable sensor along with the detection technology proposed in chapter 4 is expected to realize the in-field monitoring of a variety of veterinary drug residues.