Construction Of Solid Phase Enhanced Electrochemiluminescence Biosensor Based On Luminol And Its Derivatives

Biosensor is an analytical device composed of biological elements and sensing elements.It can detect enzymes,antibodies and cells.It has the advantages of sensitivity,low cost and real-time detection.As a powerful and advanced analytical technology,ECL have been widely used in many fields,such as medicine,food safety and environmental detection.In recent years,researchers are still exploring the functionalized nanomaterials of luminescent nanomaterials.This thesis focuses on the development of efficient luminescent functional nanomaterials,the construction of sensitive response interfaced,and the preparation of accurate and efficient ECL biosensors.1.P（ANi-Lu）-MWCNTs nanocomposites were prepared by drop coating and electropolymerization.MWCNTs were coated on the surface of graphite electrode（GE）,and then P（ANi-Lu）was electropolymerized in acidic solution.The capture probe DNA（c DNA）is connected to the surface of P（ANi-Lu）-MWCNTs nanotube electrode by amide bond.Target DNA and ferrocene labeled DNA（Fc-DNA）can be hybridized layer by layer on the surface of the electrode to form a DNA sandwich structure.During hybridization,the amount of Fc-DNA on the electrode surface was positively correlated with the target DNA.Fc can catalyze the ECL reaction of luminol,effectively improve the signal output of ECL sensor and improve the sensitivity of target DNA detection.The analytical performance of the biosensor was studied in alkaline buffer solution with and without hydrogen peroxide.Through experiments,it is found that the biosensor showed a good linear relationship in the concentration range from 1.0×10-¹⁶～1.0×10-~7 mol·L-~1,and the detection limit was 6.8×10-¹⁶ mol·L-~1 in the absence of H₂O₂.In the presence of H₂O₂,the detection limit is 2.4×10-¹⁷mol·L-~1.2.Poly（aniline-ABEI-GO）nanocomposites were prepared by drop coating and electropolymerization.Based on the nanocomposites,two sandwich ECL DNA sensors were constructed.The first sandwich ECL DNA sensor was used Fc@Au NPs as an ECL intensity controller,multiple Fc are connected to Au NPs,which significantly improves the ECL signal.Through experiments,it is found that the biosensor rendered a linear dependence over the range from 1.0×10-¹⁷～1.0×10-~7 mol·L-~1,and the detection limit was 9.7×10-¹⁸mol·L-~1.In order to compare Fc@Au NPs excellent sensitization effect of molecular groups,The second sandwich type ECL DNA sensor uses Fc as the ECL intensity controller.Under the optimum conditions,the linear range of the sensor is determined to be 1.0×10-¹³～1.0×10-~7 mol·L-~1,and the detection limit was 8.5×10-¹⁴ mol·L-~1.Through comparison,the experiment proves that Fc@Au NPs was of practical significance to reduce the detection limit of the sensor.3.Poly（aniline-ABEI-Aucore Coshell）nanocomposites were prepared by drop coating and electropolymerization.Firstly,using the seed growth method,gold nanoparticle sol as seed,cobalt shell was prepared by reducing cobalt salt with hydrazine,and Aucore Coshell nanoparticles were prepared by chemical reduction method.Then,Aucore Coshell nanoparticles was coated on the surface of graphite electrode（GE）,and then Poly（aniline-ABEI）was electropolymerized in acidic solution.Subsequently it was characterized by SEM,CV,UV and ECL.The results show that the Aucore Coshell not only has simple synthesis method and controllable product particle size and structure,but also can effectively improve the electron transfer of nanocomposites and enhance the ECL properties of composite films.Based on the nanocomposites,a sensitive ECL immunosensor for detecting c Tn I was constructed.Under the optimum experimental conditions,the biosensor rendered a linear dependence over the range from 1.0×10-¹⁵～1.0×10-~8 g·m L-~1,and the detection limit was3.47×10-¹⁶ g·m L-~1,and the immunosensor can be used for the detection of c Tn I in human serum.