| Nowadays, chemiluminescence (CL) has been proven to be a powerful analytical method due to its high sensitivity and wide dynamic range. With the rapid development of nanotechnology, the research of the chemical reactivities of nanoparticles in catalysis of CL system is now an expanding area. This thesis investigated the catalytic properties of gold nanoparticles (AuNPs) in the luminol CL system. Then combined the catalytic properties with the immunoassay and the paper-based CL device, established a homogeneous CL immunoassay method and paper-based CL method for cysteine detection. This thesis is divided into two parts, the first part is the review, which summarized the property of AuNPs and its widely application in analytical chemistry, and then focus on its application in CL analysis. The second part is as follows:1. Effect of amino compounds on catalytic ability of gold nanoparticles in luminol-H2O2chemiluminescence reactionThe study found that the catalytic ability of AuNPs in luminol-hydrogen (H2O2) CL system could be changed after the interaction between AuNPs and amino compounds, and compared with the as made AuNPs, the interaction between AuNPs and amino compounds could produce different CL intensity. In this work, a systematic research was developed about the effect of amino compounds on catalytic ability of gold nanoparticles in luminol-H2O2CL reaction. Firstly, AuNPs was used to mix with various amino compounds and then observe CL response of luminol-H2O2CL system after added the mixture of AuNPs and amino compound. The results showed that the whole catalytic ability was induced by two aspects which are the effect of electron density in nanoparticle’s conduction bands and the effect of surface negative charge density of AuNPs. This thesis provied a theoretical basis for the analysis which based on the catalytic properties of AuNPs on the luminol CL system.2. Highly sensitive homogeneous chemiluminescence immunoassay using gold nanoparticles as labelHomogeneous immunoassay is becoming more and more attractive for modern medical diagnosis because it is superior to heterogeneous immunoassay in sample and reagent consumption, analysis time, portability and disposability. Herein, a universal platform for homogeneous immunoassay, using human immunoglobulin G (IgG) as a model analyte, has been developed. This assay relies upon the catalytic activity of AuNPs on luminol-AgNO3CL reaction. The immunoreaction of antigen and antibody can induce the aggregation of antibody-functionalized AuNPs, and after aggregation the catalytic activity of AuNPs on luminol-AgNO3CL reaction is greatly enhanced. Without any separation steps, a CL signal is generated upon addition of a trigger solution, and the CL intensity is directly correlated to the quantity of IgG. The detection limit of IgG was estimated to be as low as3pg/mL, and the sensitivity was better than that of the reported AuNPs-based CL immunoassay for IgG.3. Nanoparticle coated paper-based chemiluminescence device for the determination of cysteineA laminated paper-based analytical device (LPAD) combined with AuNPs catalyzed luminol CL system for the determination of cysteine (Cys) was presented here. It is based on the principle that Cys can greatly inhibit CL signal of AuNPs-luminol-H2O2system. The paper-based device was fabricated by a low-cost cutting method, followed by lamination with two polyester films. This approach of cutting/lamination to fabricate LPAD is very similar to making a lamination picture. A good linear relationship was obtained between the CL intensity and the concentrations of Cys in the range from1.0×10-8M to1.0×10-6M with a detection limit at8×10-10M (S/N=3). This study shows the successful integration of the LPAD and the CL method. It will be of interest for use in areas such as disease diagnosis in the future. |
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