| Disease markers are important chemicals which can indicate pathogenic processes resulting from different diseases,and widely used in basic and clinical researches.Small change of disease markers in the blood can show the corresponding disease correctly and rapidly.In this thesis,the electrochemical method is used to detect nucleolin and cardiac troponin I based on Mo S2/r GO nanocomposites in terms of not only sensitivity but also simplicity.The two main researches are as follows:(1)One-pot synthesized Au NPs/Mo S2/r GO nanocomposite as sensitive electrochemical aptasensing platform for nucleolin detection.Simple,rapid,sensitive,and specific detection of cancer markers plays a pivotal role in the diagnosis and prognosis of cancer.This paper describes an alternative method for detection of nucleolin,which is a major nucleolar protein,overexpressed in several types of cancer,and is a cancer-specific target.Gold nanoparticles/molybdenum disulfide/reduced graphene oxide(Au NPs/Mo S2/r GO)was easily synthesized with hydrothermal method and characterized by transmission electron microscopy(TEM),x-ray diffraction(XRD)and x-ray photoelectron spectroscopy(XPS).Combining the properties of large surface area and good electrical conductivity of Au NPs/Mo S2/r GO with the high affinity and specificity of aptamer,a smart hierarchically self-assembled electrochemical aptasensor was established for the specific and sensitive nucleolin(as a model analyte)detection.Under the optimized conditions,Au NPs/Mo S2/r GO based aptasensor exhibited a great performance for the detection of nucleolin with a linear response from 0.5 n M to 1.0 ?M and a low detection limit of 0.5 n M.In addition,this electrochemical aptasensor had good reproducibility and stability towards nucleolin.Besides,the practicability of the TNA(thiolated nucleolin aptamer)/Au NPs/Mo S2/r GO was demonstrated by analysis of nucleolin in the blood sample.This work paves a promising way for the facile synthesis and design Mo S2/r GO nanocomposite-based electrochemical aptasensor for testing tumor markers in clinical diagnostics.(2)A sensitive electrochemical aptasensor for determination of cardiac troponin I basedon Cu NWs/Mo S2/r GO nanocomposite.Copper nanowires/molybdenum disulfide/reduced graphene oxide(Cu NWs/Mo S2/r GO)nanocomposite was synthesized and used for the electrochemical detection of cardiac troponin I(c Tn I),which is known as the gold standard biomarker for the early diagosis of acute myocardial infarction(AMI).The results of scanning electron microscope(SEM),energy dispersive x-ray spectrometer(EDX)and XPS showed that the nanocomposite was successfully prepared and Cu NWs was uniformly dispersed on Mo S2/r GO.The electrochemical methods,including cyclic voltammetry(CV),differential pulse voltammetry(DPV)and electrochemical impedance spectroscopy(EIS),were used to investigate the electrochemical performance.And it exhibited excellent electrical conductivity and sensitive detection of c Tn I due to the synergistic effect of r GO,Mo S2 and Cu NWs and high affinity and specificity of aptamer.Under optimal conditions,the linear range of the aptasensor was from 5 ? 10-13 to 10-10 g m L-1,and the detection limit was 5 ? 10-13 g m L-1.Moreover,the electrochemical aptasensor was applied to the quantitative analysis of c Tn I in human blood samples with satisfactory results,which indicated the prepared aptasensor has great potential in clinical samples. |
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