Synthesis Of Functionalized Luminol/Polypyrrole Nanocomposites And Its Analytical Applification In Immunoassay

Conductive polymers,also known as"synthetic metals",have good thermal stability and oxidation resistance,excellent electrical and mechanical properties.It has a good application prospect in battery electrodes,electronic textiles,various biomedical devices,biosensors and so on.Among the conductive polymers,polypyrrole（PPY）has become one of the most concerned polymers because of its good biocompatibility,simple synthesis method,high conductivity and high stability.In recent years,nanocomposites have attracted wide attention in the field of electrochemiluminescence（ECL）because they can improve the mechanical and electrical properties of the composites.Polymer nanocomposites can combine the properties of matrix with those of dopants to create new materials with improved optical,electrical,mechanical and thermal properties.In this thesis,three kinds of luminescent functionalized PPY-luminol,PPY-luminol-Au NPs,PPY-luminol-GO nanocomposites with good ECL properties were successfully prepared by chemical oxidation.Based on PPY-luminol-Au NPs,PPY-luminol-GO nanocomposites,two novel ECL immunosensors were constructed,and the sensitive detection of carbohydrate antigen153（CA153）and prostate specific antigen（PSA）was achieved respectively.The paper mainly includes the following contents:1.PPY-luminol nanocomposites were successfully prepared by chemical oxidation.The nanocomposites were characterized by high resolution transmission electron microscope（HR-TEM）,UV-Vis absorption spectra（UV-Vis）,molecular fluorescence spectrum（MFS）and electrochemical impedance spectroscopy（EIS）.Through HR-TEM characterization,it is found that spherical PPY has uniform particle size,and PPY nanospheres with uniform particle size can not only be used in ECL analysis,but also be expected to be labeled on DNA,antibody or antigen for chemiluminescence（CL）or labeled ECL analysis,which can develop biosensors for detecting biological macromolecules such as protein,enzyme and DNA.2.PPY-luminol-Au NPs nanocomposites were prepared,and on the basis of this material,a sensitive and label-free ECL immunosensor for the detection of CA153 was developed.Iron element was also detected in the nanocomposites.Firstly,polypyrrole（PPY）nanoparticles were synthesized by chemical oxidation with Fe Cl₃ as initiator,then luminol and Au nanoparticles（Au NPs）were combined with PPY nanoparticles through electrostatic interaction to form PPY-luminol-Au NPs composite nanoparticles.The PPY-luminol-Au NPs composites showed excellent ECL activity due to the bi-catalysis of gold nanoparticles and iron ion on the ECL of luminol.Furthermore,the nanocomposites showed good film-forming property,and it can be fixed on electrode surface without the assistance of other film-forming materials.The ECL immunosensor showed a good linear relationship in the concentration range of 0.001 to 700 U/m L,and the detection limit was 5.8×10^-4 U/m L（S/N=3）.Furthermore,the ECL immunosensor was applied to the determination of CA153 in practical human serum sample.3.PPY-luminol-GO nanocomposites were successfully prepared by chemical oxidation method.The catalytic action of GO made it have excellent ECL performance,and PPY had better dispersity after adding GO.There isπ-πinteraction between PPY and GO,which can promote charge transfer.Therefore,PPY-luminol-GO modified ITO electrode has faster electron transfer speed and can load more anti-PSA.Based on the inhibitory effect of PSA on ECL signal of this material,a new ECL immunosensor for detecting PSA was prepared.The ECL immunosensor has a good linear relationship in the concentration range of 1.0×10^-13 to 1.0×10^-7mol/L,and the detection limit is 3.5×10^-14mol/L（S/N=3）.The immunosensor can be applied to the detection of PSA in human serum.