Detection Methods Of Uranyl Based On Functional Nucleic Acids And Gold Nanoparticle

Uranium is a radioactive metal, which can cause severe adverse effects on humanhealth by its high toxicity and radioactivity, such as damage of kidney and brain,disorder of digestion system and immune function. Up to now, the analyticaltechniques for determination of uranium require expensive and complicatedinstruments, tedious and painstaking procedures and complex sample preparation. Itwill be helpful to develop a method for simple, sensitive and high selectivity detectionand quantification of uranium in pollution warning, safety evaluation, environmentalremediation and minimization of uranium exposure to humans and related adversehealth effects.In the chapter2, a novel sensitive method has been developed for the detection ofuranium based on an unlabeled DNAzyme-gold nanoparticle system by usingresonance light scattering （RLS）. In MES buffer solution of pH4.5, DNAzyme splitand released ssDNA with uranyl. Upon addition of NaCl solution, a rolling state ofssDNA appeared that could protect AuNPs from aggregating and decrease RLSintensity. It was found that the decreased RLS intensity was propotional to theconcentration of uranyl over the range of2.08×10^-92.00×10^-8mol·L^-1, and thelinear regression equation was ΔI_RLS=59.45+14761c (μmol·L^-1), r=0.9852. Thelimit of detection （LOD） for uranyl was6.23×10-10mol·L^-1. The proposed methodwas simple, fast, selective and sensitive.In the chapter3, a novel sensitive method has been developed for the detection ofuranium based on a labeled DNAzyme-gold nanoparticle system by using enhancedresonance light scattering （RLS）. A uranyl-specific DNAzyme was attached to AuNPs.In MES buffer solution of pH4.5, upon addition of UO22+, the DNAzymefunctionalized AuNPs were induced to aggregate, resulting in increasing of RLSintensity. The I signal linearly correlated with the concentration of UO22+over the range of1.36×10^-81.50×10^-7mol L^-1. The limit of detection （LOD） was4.09×10^-9mol·L^-1for labeled method. The proposed method was selective, repeatability andsensitive.In the chapter4, a new aptamer was abtained by converting to A from rA whichwas cleavage site of uranyl-specific DNAzyme. Based on the aptamer, we developeda new method for the detection of uranium. The RLS intensity linearly correlated withthe concentration of uranyl over the range of2.08×10^-92.00×10^-8mol·L^-1, and thelinear regression equation was ΔI_RLS=70.88+4.100c (×10^-8mol·L^-1), r=0.9889.The limit of detection （LOD） for uranyl was6.70×10^-9mol·L^-1.The proposed methodwas simple and rapid.