Fabrication And Application Of Electrochemiluminescence Immunosensors Based On Luminol Nanocomposite

Electrochemiluminescence(ECL)is the phenomenon that the luminescent material is produced by the electron gain and loss on the electrode surface.In recent years,more and more researchers have paid attention to electrochemiluminescence biosensor,which has been widely used in the fields of pharmaceutical analysis,immunoassay,DNA analysis and clinical analysis.A new type of functional nano materials because of its special nano-structure,strong adsorption capacity,large surface area which can greatly improve the biological molecules(such as enzyme,DNA,etc.)the loading and labeling of biomolecules,catalytic reaction,accelerate the electron transfer and increase the current signal,provide a new way for the research and application of bio electrochemistry sensor.It can not only improve the performance of electrochemiluminescence sensor,but also can be used to adsorb some biological proteins and biomolecules.In this paper,the multi-walled carbon nanotubes-platinum-luminol(MWCNTs-Pt-luminol)was used as an immunological platform to construct an ultra-sensitive ECL immunosensor to detect CA19-9;MoS2-PEI-Au and Au@BSA were used as a sensing platform and labeled luminol,respectively,to construct a sensitive ECL immunosensor for detection of AFP;luminol-labeled Pt@BSA and MCS-Fc nanomaterials were used to modify the sensor interface to detect the CA15-3.The dissertation includes four chapters:In chapter 1,the background knowledge and significance of this dissertation have been introduced with the emphasis on the following aspects,mechanism of ECL and functional nanomaterials,electrochemical immunosensor in real-life applications.In chapter 2,MWCNTs-Pt-luminol nanocomposites were synthesized,and characterized by UV-Vis absorption and transmission electron microscopy(TEM).The above-mentioned functional materials were assembled to form an ultrasensitive ECL sensor for the detection of CA19-9.The immunosensor exhibited good reproducibility and stability with a low detection limit of 0.000046 U/m L,and satisfactory results in the actual serum sample determination.In chapter 3,colloidal gold functionalized MoS2 nanosheet via electrostatic adsorption to synthesis of MoS2-PEI-Au nanocomposite material is fixed on the electrode surface as the sensing platform.While Au@BSA provided a larger surface area for labeling luminol and immobilized secondary antibodies(Ab2).The sensitivity of AFP was detected by the combination of antigen and antibody by sandwich type ECL immunosensor.Upon the optimization of assay conditions,the proposed immunosensor displayed wide linear range from 0.0001ng/mL to 200.0ng/m L with limit of detection of 0.00001ng/m L.In addition,the sensor shows excellent performance in the detection of real samples and provides great potential for the detection of other clinical biomarkers.In chapter 4,the mesoporous carbon sphere-ferrocene(MCS-Fc)has a large specific surface area,good electrical conductivity,and enhanced catalytic activity of hydrogen peroxide as a base material to enhance the electrochemical luminescence signal.Luminol-Pt@BSA-Ab2 as a signal probe,after the incubation of CA15-3,the successful construction of an sandwich-type ECL immunosensor to achieve the CA15-3 ultra-sensitive detection.Upon the optimization of assay conditions,the proposed immunosensor displayed wide linear range from 0.0005-500.0 U / mL with limit of detection of 0.000025U/mL.The immunosensor has a wide linear range and a lower detection line.In addition,the construction of the immune sensor for clinical research and other biomolecules and protein detection provides a certain reference value.