| In this dissertation, vatious chemiluminescence systems, the synthesis and properties of chemiluminescent functionalized gold nanomaterials (CF-AuNMs) and their applications in bioassays were reviewed. Recently, CF-AuNMs have been used for various types of biolabeling and life-related molecular diagnostics due to their unique optical, catalytic, and biocompatible properties. However, limited CF-AuNMs have been reported. Currently, the fabrication protocol of CF-GNMs is to graft the CL reagent indirect on the surface of GNMs by virtue of bridge molecules. The used CL reagents include Ru-complex and luminol. Although the protocols can achieve very high sensitivity for bioassays, there are some drawbacks. For example, indirect synthesis process needs several reaction and purification steps, thus is complicated and time-consuming. These problems limit the practical applications of these protocols. Therefore, it is highly desired to exploit the new synthesis strategy for the preparation of new CF-GNMs with high CL efficiency, stability and biocompatibility, which is of great value in the fields such as public health, food safety, and environmental science and so on. In this work, direct synthesis of CF-AuNMs using luminol and its derivatives as reductant and stabilizing reagent and their applications in CL bioassays was explored.The main results are as follows:1. A novel electrochemiluminescence (ECL) sandwich-type immunosensor for human immunoglobulin G (hIgG) on a gold nanoparticle modified electrode was developed by using N-(aminobutyl)-N-ethylisoluminol (ABEI) labeling. The first goat-anti-human IgG antibody was immobilized on a gold nanoparticle modified electrode, then human IgG and the ABEI-labeled second goat-anti-human IgG antibody was conjugated successively to form a sandwich-type immunocomplex. ECL was carried out with a double-step potential in carbonate buffer solution (CBS) containing 1.5 mM H2O2. The ECL intensity increased linearly with the concentration of hIgG over the range 5.0– 100 ng/mL. The limit of detection was 1.68 ng/mL (S/N = 3). The relative standard deviation was 3.79% at 60 ng/mL (n = 9). The present immunosensor is simple and sensitive. It has been successfully applied to the detection of hIgG in human serums.2. An ultrasensitive electrochemiluminescence (ECL) immunosensor based on luminol functionalized gold nanoparticle (AuNP) labeling was developed by using human immunoglobulin G (hIgG) as a model analyte. The primary antibody biotin-conjugated goat-anti-human IgG was first immobilized on a streptavidin-coated AuNP modified electrode, then the antigen (human IgG) and the luminol functionalized AuNP-labeled second antibody was conjugated successively to form a sandwich-type immunocomplex, i.e. immunosensor. ECL was carried out with a double-step potential in carbonate buffer solution containing 1.0 mmol/L H2O2. Since thousand of luminol molecules were coated on the surface of AuNPs to realize labeling of multiple molecules with CL activity at a single antibody and the amplification of AuNPs and biotin-streptavidin system were utilized, luminol ECL signal could be enhanced greatly, finally resulting in extremely high sensitivity. The ECL method shows a detection limit of 1.0 pg/mL (S/N = 3) for hIgG, which is superior to all previously reported methods for the determination of hIgG. Moreover, the proposed method is also simple, stable, specific, and time-saving, avoiding the complicated stripping procedure during CL detection and the uncontrollable synthesis of irregular nanoparticles compared with other chemiluminescence immunoassay based on AuNP labeling. Additionally, the labeling procedure is also superior to that of other reported multilabeling strategies, such as Ru complex-encapsulated polymer microspheres, and most of Ru complex-encapsulated liposomes in simplicity, stability, labeling property and practical applicability. Finally, hIgG in human serums was successfully detected by this ECL immunosensor.3. It was found that the CF-AuNMs could be prepared by reducing HAuCl4 with N-(aminobutyl)-N-ethylisoluminol (ABEI) in aqueous solution at room temperature through a seed growth method. Transmission electron microscopy, UV-visible spectroscopy, X-ray photoelectron spectroscopy, and powder X-ray diffraction analysis were used to characterize the morphology and surface component of the CF-AuNMs. The results indicated that various morphologies (mono-disperse sphericity, assembled chain of sphere AuNPs, assembled qusi-network of sphere AuNPs, assembled network of sphere AuNPs) of CF-AuNMs could be obtained. Moreover, ABEI and N-(aminobutyl)-N-(ethylphthalate) (ABEI's oxidation product ) were bounded on the surface of the AuNPs through weak Au-N covalent bond. The assembling mechanism of the various morphologies of CF-AuNMs was discussed by theoretical calculation and UV-visible spectroscopy. Finally, the CF-AuNMs exhibited good CL activity in alkaline solution and were successfully applied in bio-probe for bioassays. 4. Iso-luminol functionalized gold nanomaterials (AuNPs) were synthesized in high yield by a simple seeding approach using chemiluminescent (CL) reagent iso-luminol as reductant in the presence of HAuCl4, AgNO3 and cetyltrimethylammonium bromide (CTAB). The morphology characterization of iso-luminol functionalized AuNPs was performed by UV-visible spectroscopy and transmission electron microscopy, showing that tadpole-shaped gold nanoparticles (AuNTps) were obtained. Subsequent experiments reveal that the amounts of added seed colloids, added AgNO3, the concentrations of iso-luminol and CTAB in the growth solution play critical roles in the formation of well shaped AuNTps. The surface state of AuNTps was characterized by UV-visible spectroscopy and fluorescence spectroscopy, indicating that iso-luminol and 4-aminophthalate (iso-luminol's oxidation product) were bounded on the surface of AuNTps. The CL behavior was studied by static injection CL experiments, demonstrating that AuNTps were of CL activity. Finally, the growth mechanism of AuNTps was also discussed.
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