Construction Of New Nano Optical Biosensor And Its Application In Pesticide Residue Detection

The environmental pollution caused by pesticide residues is still one of the great threats to the progess and development of the world.Establishing and developing timely,simple,accurate and highly sensitive pesticide residue detection method is the basis,precondition and even key link of prevention,control and disposal of pesticide residue pollution.In recent years,with the development of nano science and technology,based on the excellent performance of nano materials(AuNPs,QDs)to build the nano biosensors due to a short response time,low cost advantages,to provide on-site real-time detection of pesticide residue is a simple,rapid,accurate and effective method.This paper made full use of the special advantage of gold nanoparticle on the optical performance,quantum dots,the unique optical properties,plant esterase high specificity recognition,from the design and construction of nano optical biosensors two aspects,FRET,IFE,and other enzyme inhibition principle designed and constructed a series of nano optical biosensor based on the detection and the performance of the sensor was studied.The main research work of this thesis are as follows:(1)Based on the FRET principle,the Au NPs-RB nano optical biosensor was constructed and used for the detection of pesticide residues in microtrace cartapThe development of acute toxicity of cartap pesticide residue and potential genotoxicity poses a great threat to human health.In this paper,on the basis of the principle of FRET to make full use of gold nanoparticles(AuNPs)excellent photoelectric properties and rhodamine(B)fluorophore high quenching efficiency,build a fluorescein(rhodamine B)as the donor,AuNPs as receptor of new nano optical biosensor for detection of trace concentrations of cartap.A systematic study on detection principle of AuNPs-RB nano optical sensor to cartap and to explored the optimal conditions for the detection of cartap;Under the optimum conditions,the linear range of AuNPs-RB nano optical biosensor detection of 0-180 nM cartap pesticide residues,the detection limit was 0.88 nM.Results showed that compared with the traditional cartap pesticide residue detection methods,AuNPs-RB nano optical sensor had a low detection limit,detection of cartap in actual sample had great application prospect.(2)Based on IFE,the Au NPs-QDs nano optical biosensor was constructed and used for the detection of the residue of trace cartapPesticide residues of cyanide can cause serious endocrine disruption,birth defects,reproductive tumors and other serious diseases,and posed a great threat to human health.In this paper,a new type of nano optical sensor based on internal filtering(IFE)between AuNPs and CdTe QDs had been developed.The AuNPs-QDs nano optical sensor was constructed for the first time to detect the specificity,sensitivity and sensitivity of the dual optical signal.In this paper,the detection principle of AuNPs-QDs nano optical biosensor for cyanide was systematically studied,and the optimum conditions for detection of cyanide were discussed.Under the optimum conditions,the linear range of AuNPs nano optical sensors for colorimetric detection of trace cyanazine pesticide residue was 2-9 ?M,the detection limit was 0.2201 ?M,which indicated that AuNPs nano optical sensor for cyanazine colorimetric detection in the condition of low concentration sensitivity can be achieved very satisfactory;Under the optimum conditions,the linear range of AuNPs-QDs nano optical sensor fluorescence detection construct the trace of cyanazine residues was 0.5-9 ?M,the detection limit was 0.1578 ?M,which indicated that AuNPs-QDs nano fluorescence sensor for detecting the fluorescent cyanazine the sensitivity can be achieved very satisfactory in low concentration conditions.The selectivity of the sensor was evaluated by the determination of 12 cyano groups of pesticides;Results showed that,building of AuNPs-QDs nano optical sensor had a low detection limit,good repeatability,high selectivity(strong anti-interference),reliability and other advantages,and in the actual samples and standard experiment has obtained the very good recovery,was expected to be used for rapid detection of actual samples of cyanazine.(3)Based on plant esterase(PLaE)detection and mechanism of optical biosensor for fenitrothionPlant esterase is the three enzymes markers for detecting pesticide residues,wide sources,low price,in the development of enzyme sensor type pesticide residues have huge potential application value,but the plant esterase(PLaE)purification methods exist steps more,lack of yield was lower.In this study,a new purification technique,TPP,was used for the purification of PLaE for the first time.The factors affecting the purification of PLaE by the three phase partition method were systematically studied;On the basis of single factor experiment,the response surface method and four factors and three levels of the Box-Behnken central composite experimental design method to optimize the purification process of PLaE,and characterized by SDS-PAGE gel electrophoresis,fluorescence;The high purity PLaE was used to construct PLaE fluorescent sensor,and the optimum conditions for the detection of fenitrothion were discussed;Under the optimum conditions,the linear range of PLaE optical biosensor fluorescence detection construct the trace of fenitrothion pesticide residue was 1 ng/ml-70 ng/ml,the detection limit was 0.74286 ng/ml,which indicates that the sensor was constructed in this paper for fluorescence detection of fenitrothion in low concentration conditions and sensitivity can be achieved very satisfactory.Combined with fluorescence quenching method system to study the PLaE and fenitrothion quenching constants,combining with the parameter and thermodynamic parameters,types of forces,illuminated the PLaE fenitrothion fluorescence quenching method between the mechanism and the mechanism of action.(4)Based on the principle of enzyme inhibition,a AuNPs-PLaE nano optical biosensor was constructed and applied to the detection of trace fenitrothion pesticide residuesThis was the first time coupling the gold nanoparticles and the PLaE,the green synthesis of gold nanoparticles as an indicator of plant esterase and pesticide effect signal into optical signal,based on organophosphorus pesticides(OPs)on plant esterase enzyme(PLaE)inhibitory activity was successfully constructed a new type of AuNPs-PLaE nano-optical biosensor for the colorimetric detection of fenitrothion.In this paper,the principle of AuNPs-PLaE nano optical biosensor was studied systematically,and the optimum conditions for the detection of fenitrothion were discussed;Under the optimum conditions,the linear range of AuNPs-PLaE nano-optical biosensors for colorimetric detection of trace fenitrothion pesticide residue was 0.28-19.6 ?g/m L,the detection limit is 0.084 ?g/m L,which indicated that AuNPs-PLaE nano optical sensor for fenitrothion colorimetric detection in the condition of low concentration sensitivity can be achieved very satisfactory;Compared with the traditional plant esterase enzyme inhibition sensors,AuNPs-PLaE nano-biological sensors did not need to determine enzyme activity and added additional substrate,had rapid response,easy intuitive,advantage of high sensitivity,selectivity and good repeatability,which could realized real-time and on-line rapid detection of fenitrothion,and had better innovation.