Studies On Copper Ion And Gene Detection Based On Functional Nanomaterials

Copper is one of the transition metals and the third most abundant trace element in human body.It is present in all types of cells and tissues in minute amounts and is crucial for both physiological and pathological activities.And since most biological processes and environmental applications are carried out in the water medium,the efficiency of the sensor in the water medium is crucial.Therefore,it is urgent to develop new methods for the selective and sensitive detection of copper ions in aqueous solutions.In addition to metal ions,biomolecules（such as DNA,m RNA,etc.）are also closely related to the occurrence of many diseases,and genetic testing of Chinese medicinal materials is a way of quality control,which can better treat diseases.Therefore,the construction of a convenient and sensitive detection strategy for the detection of biomolecules has important research significance for the prevention,development and treatment of clinical diseases.In Chapter 2,a novel electrochemical luminescence sensorbased on bipyridine ruthenium MOF nanoparticles and AE-TPEA was synthesized:We designed and synthesized AE-TPEA,which canselectively detect Cu²⁺,and combined it with Ru MOFs（UiO-Ru）,prepared based on UiO-67 as prototype,through amide reaction to form a whole porous MOFs nanomaterial UiO-Ru-TPEA.They were characterized by nuclear magnetic resonance spectroscopy,mass spectrometry,Fourier transform infrared spectroscopy（FT-IR）,scanning electron microscopy（SEM）,X-ray spectroscopy（XPS）and X-ray diffraction（XRD）.The UiO-Ru-TPEA modified sensor is a kind of sensor with selective detection ability of Cu²⁺,and its luminescent group is bipyridine ruthenium group(Ru（dcbpy）₃²⁺).It showed excellent electrochemical luminescence response,and the electrochemical luminescence intensity decreased or even quenched after adding Cu²⁺.The electrochemical luminescence intensity measured by UiO-Ru-TPEA-modified sensors showed no or little change even in the presence of other common interfering ions in high concentrations.The LOD is 0.47 n M,indicating that it has high sensitivity and selectivity for target copper ions.The prepared Cu²⁺sensor has been successfully applied to the determination of Cu²⁺in mouse blood samples without obvious interference.The experimental results show that the sensor can selectively analyze Cu²⁺in blood as low as 0.315 n M.It is a promising candidate device for the detection of Cu²⁺,which can be used in clinical laboratory.In Chapter 3,it is introduced that UiO-Ru-TPEA sensor can also be used for electrochemical detection.We use DPV todetect Cu²⁺in solution.The results show that the current signal has a good linear relationship with the logarithm of Cu²⁺concentration.The LOD is 2.13 n M and the detection range is 5 n M～80μM.The Cu²⁺concentration in mouse blood samples was also successfully detected by this method,with a detection limit of 1.13 n M and a detection range of 2 n M⁷5 μM.The developed electrochemical luminescence and electrochemical analysis methods are compared with other detection methods,showing better or comparable analytical ability in linear range and LOD.In Chapter 4,a highly integrated,biostable,and autonomous electrochemical DNA walker sensor was rationally designed by a simple assembly of a Mn²⁺-dependent DNAzyme-powered DNA walker with nanoscale Mn²⁺@MOFs containing free carboxylic acid groups(UiO-66（Zr）-（COOH）₂.In this study,the release of Mn²⁺from Mn²⁺@MOFs was exploited to drive the autonomous and progressive operation of the DNA walker,and the DNAzyme-driven DNA walker was constructed by the co-modification of walking strands and track strands onto the gold electrode（GE）surface.The walking strand was a single-stranded DNA containing a DNAzyme sequence,which was pre-silenced by the locking strand.The track strand was a specially designed DNA sequence that the target can hybridize with the locking strand;hence,the walking strand is unlocked,and the liberated DNAzyme catalyzes the cleavage of track strands to drive the DNA walker operation,shifting tetraferrocene away from the electrode and producing a significant signal change.A detection limit of 0.038 p M was obtained with our new system,exhibiting a wide linear range from1.5625×10^-9mol/L to 1×10^-13mol/L.Successful detection of let-7a and C.sinensis DNA in actual samples.The proposed approach provided a novel means for constructing an highly integrated,automated,and DNAzyme-driven DNA walker for bioanalysis.