| Gold nanoparticles are one of the most important nanomaterials and have been widely studied owing to their unique physical and chemical characteristics. According to the simple synthesis method, chemical stability and high resistance to surface oxidation, beside the enhanced chemical reactivity, gold nanoparticle is an important nanomaterial for use as a reactive center or as a nanocatalyst in many chemical reactions. But it must be mentioned that the most important factor in the catalytic behavior of gold nanoparticles is the availability of many low-coordinated gold atoms on the surface of nanoparticles. Therefore, unsupported gold nanoparticles could be used in catalyzing liquid-phase chemical reactions.Chemiluminescence (CL) represents a versatile, sensitive tool with a wide range of applications in diverse fields, such as biotechnology, pharmacology, molecular biology and clinical and environmental assays. CL, light emission induced by chemical reactions, has been intensively investigated for many years. Traditionally, the study of CL was limited to molecular systems. Recently, attention has been paid to nanoparticle systems. CL sensitivity could be increased when nanoparticles were used as chemiluminescent reactants or catalysts in CL analysis. Nanoparticles also could be used as biological tags in CL analysis. This thesis contains three sections. Section one is a review, which involves the history, the basic principles, characteristics and the main liquid systems of CL, and applications of CL systems in pharmaceutical analysis during 2005 and 2007, and principles and applications of chemiluminescence immunoassay. We also summarized the recent developments of gold nanoparticles in CL.In the second section, it has been found that tetracycline hydrochloride can be quantified by the luminal-hydrogen peroxide-gold nanoparticles CL system. Tetracycline hydrochloride, which is a kind of tetracycline antibiotics, is used widely. Tetracycline hydrochloride analysis methods include microbiological assays, chromatographic assays, spectrophotometry and electrochemical assays. Although these methods have their respective advantages, they also have shortcomings, such as poor sensitivity, time-consuming procedures or unsuitability for automatic or continuous analysis. In this study, it was found that gold nanoparticles enhanced the CL of the luminal-hydrogen peroxide system and those tetracycline hydrochlorides inhibited these CL signals. Under the optimized conditions, the CL intensity was linearly related to the concentration of the tetracycline hydrochloride within the range of 1.6~25μg/mL, with a detection limit (3σ) of 1.1μg/mL. The relative standard deviation was 2.6% for 15μg/mL tetracycline hydrochloride solution. This method has the advantages of simple operation, high sensitivity and fast response. The method has been applied to the determination of tetracycline hydrochloride in human urine, with satisfactory results.In the third section, we developed a novel and sensitive chemiluminescent immunoassay of human immunoglobulin (HIgG) by use of highly active, spherical shaped gold nanoparticles as label and amplified luminal- hydrogen peroxide chemiluminescent system. First, the rabbit anti-HIgG antibody (primary antibody) was immobilized on dextran-Fe3O4 magnetic nanoparticles, which was used as a solid support. Then a sheep anti-HIgG antibody (secondary antibody) was attached to the surface of gold nanoparticles with electrostatic interaction. Finally, the sandwich-type complex was formed in this protocol by the primary antibody immobilized on the magnetic nanoparticles, HIgG antigen in the sample and the secondary antibody labeled with gold nanoparticles, and was separated in magnetic field, and was detected with CL signals. The chemiluminescence intensity depended linearly on the logarithm of the concentration of HIgG over the range of 0.5~1000ng/mL and detection limit (3σ) was 0.37ng/mL. The relative standard deviation was 3.8% for 10ng/mL HIgG solution. This method has been successfully applied to the determination of HIgG in human serum sample and showed extensive potential applications in analytical and bioanalytical chemistry.
|
PDF Full Text Request