| Graphene is a two-dimensional and zero band gap carbon crystal with a singleatomic layer that has recently attracted intense interest due to its unusualelectrochemical properties, high thermal conductivity, excellent mechanical flexibilityand optical performance. Graphene oxide (GO) has the similar structure and propertywith graphene as its water-soluble derivative. And the hydrophile of GO is improvedwith the introduction of oxygen-containing groups. In addition, GO displays severaladvantages over other carbon nanomaterials, e.g. ease of preparation, low-cost,stability, large accessible surface area and good biocompatibility. Now, GO has beenexploited with a wide range of applications in bioanalysis. CL is a quantificationmethod via the production of electromagnetic radiation by a chemical reaction. Themethod has many advantages, such as high sensitivity, easy operation and simpleinstrumentation. In this paper, we researched the applications of GO in CL. Theresearch in my assay consists of three parts:Chapter1: Review-research progress of graphene and GOThis chapter descripted the properties, synthetic method, interaction with othersubstances and applications in chemical and biological sensing of graphene and GO.Chapter2: Graphene Oxide-Catalyzed Luminol Chemiluminescence and ItsAnalytical ApplicaitonsIn this work, we researched the catalytic activity of graphene oxide (GO) on theluminol-H2O2chemiluminescence (CL) system, a popular model CL system.Furthermore, by taking advantage of a magnetic separation/mixing process andcatalytic activity of GO label, a GO based CL method for the noncompetitiveimmunoassay of a human immunoglobulin G (Ig G) has been developed. Thesandwich-type complex of labeled GO could trigger the CL reaction of luminol andH2O2. The CL signal was directly proportional to the concentration of human IgG inthe standard or sample. Under the opitimized conditions, a linear plot of the CLintensity of the immunosensor against the logarithm of the concentration of humanIgG (2.5to100pg/mL) was obtained. The detection limit was1.2pg/mL (~7.5fM),which is comparable with or better than other immunoassays. Compared to the traditional label HRP, GO is much cheaper and more stable, indicating thisimmunoassay method may find wide applications in different kinds of bioassays.Chapter3: Label-free chemiluminescent ATP aptasensor based on grapheneoxide and an instantaneous derivatization of guanine basesIn this work, a novel label-free chemiluminescent (CL) aptasensor has beendeveloped for rapid and facile detection of adenosine triphosphate (ATP, as modelanalyte) using graphene oxide (GO) nano-platform. The strategy relies on1) thepreferential binding of GO to single-stranded DNA (ssDNA) over rigiddouble-stranded DNA (dsDNA) or aptamer-target complexes,2) the instantaneousderivative reaction between phenylglyoxal (PGO), a special CL reagent as thesignaling molecule, and guanine nucleobases (G) of aptamer strands adsorbed on thesurface of GO. In the absence of ATP, the aptamers adsorbed onto the surface of GOleading to a strong background CL signal. Conversely, in the presence of ATP, theaptamers formed the aptamer-ATP complexes which had weak binding ability to GOresulting in a significant CL signal decrease. The CL intensity was adversely relatedto the ATP concentration in the assay solution. Under the optimized conditions, thelabel-free ATP aptasensor provided a linear range from2to80nmol with a detectionlimit of1.4nmol. The aptasensor also showed high selectivity. The method presentedhere holds the advantages of being label-free, rapid, sensitive, cost effective, andselective, which would shows great promise for clinical application. |
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