Application Of Electrochemical Biosensor Based On Porous Metal And Covalent Organic Material In The Detection Of Disease Markers

Covalent organic framework materials?COF?have high stability?thermal stability and chemical stability?,high specific surface area and large pore volume.After loaded with metal nanoparticles,their biocompatibility can be improved with a wide range of applications.In this thesis,two covalent organic framework materials?COF-LZU1 and COF-TpPa-1?were synthesized and loaded with Pt,Au nanoparticles to synthesize Pt NPs/ COF-LZU1 and Au NPs/COF-TpPa-1 composites materials.The composites materials were modified on the glassy carbon electrode surface as immobilized matrix to immobilize the antibody,respectively.Moreover,metal organic framework loaded with Au NPs?Au NPs/Cu-TPA?,Pd NPs/MnO₂ and Ir /MnO₂ were prepared as label to construct electrochemical immunosensors for the determination of carcinoembryonic antigen?CEA?,c-reactive protein?CRP?and prostate-specific antigen?PSA?,respectively.?1?A novel and simple electrochemical immunoassay for CEA was developed using Au nanoparticles loaded-metal-organic frameworks?Au NPs/Cu-TPA?as signal probe and electrochemical reduction of graphene oxide on the surface of electrode to immobilize CEA antibody?Ab1?.MOFs?Cu-TPA?contain large amounts of Cu2+ions,which can be used as stable electrochemical signals to achieve the detection of CEA.This new class of signal probe differs from traditional probe because it does not require pre-treatment and acid treatment,and easy to load noble metal for the immobilization of antibody,which will simplify the detection steps and shorten the detection time greatly.This immunosensor was ease to operate with good sensitivity.Under the optimum conditions,There is a linear relationship between signal and CEA antigen concentration within 0.1–80 ng?mL–1 with detection limit of 30 pg/mL.The correlation coefficient was 0.9987.This developed CEA immunosensor can be used to detect CEA in real sample.?2?Covalent organic framework material?COF-LZU1?was synthesized using solvent thermal method.Then,metal Pt was reduced on the COF material utilized themethod of electrochemical reduction.A sandwich immunosensor for CRP was prepared using Pt NPs/ COF-LZU1 composite material as immobilized matrix and Pd NPs/MnO₂ composites materials as label.The reduction current of hydrogen peroxide catalyzed by Pd NPs/MnO₂ was determined by chronoamperometry?i-t?.The concentration of CRP has a good linear relationship with response current in the range of 1-150 ng /mL with the linear correlation coefficient of 0.9961 and detection limit of 0.33 ng /mL.This sensor has good stability and high sensitivity.?3?COF-TpPa-1 was prepared by high-temperature solvothermal method.Au NPs/ COF-TpPa-1 composite materials were prepared by loading the gold nanoparticles onto the COF-TpPa-1 material by reduction method.Au NPs/COF-TpPa-1 was modified onto the glassy carbon electrode to immobilize CRP antibody and construct a label-free immunosensor for CRP.Au NPs/COF-TpPa-1modified on the electrode can directly catalyze the reduction of p-nitrophenol.The binding of CRP antibody and CRP antigen can hinder the transfer rate of redox probe p-nitrophenol on the surface of electrode,leading to decrease of response current signal of p-nitrophenol.There is a linear relationship between signal and CRP antigen concentration within 0.01 to 150ng/mL with detection limit of 3 pg/mL.The correlation coefficient was 0.9980,This sensor is simple method with low detecting limit and high sensitivity.?4?A novel nanomaterials of MnO₂ loaded with Ir was used to label PSA antibody as a signal probe.Ag was electro-reduced to the surface of the COF-LZU1 modified-electrode to immobilize PSA antibody?Ab1?.An electrochemical immunosensor was constructed and used to detect prostate-specific antigen?PSA?.The synthesized MnO₂ nanomaterials have many advantages such as porous channel,large specific surface area and so on,which greatly improve the electrochemical signal.Under the optimal conditions,the linear range of this sensor is 0.01-150 ng / m L with the detection limit of 3 pg/mL and the linear correlation coefficient of 0.9887.The PSA immunosensor developed in this paper can be used for the determination of PSA in real samples.This immunosensor is easy to operate with.high sensitivity.