Application Of MOF-Based Integrated Electrochemical Sensor In Disease Detection

With the development of society,the rapid detection of disease molecules plays an important role in health monitoring and disease prevention.Electrochemical sensors have good application prospects in rapid detection of diseases due to their advantages of easy operation,low cost,high selectivity and sensitivity.The traditional rigid glassy carbon electrodes have limited their application in rapid detection due to their large size,difficulty in bending,and difficulty in integration.In recent years,nano-sensing materials have gradually entered the public eye,and MOF materials have become an ideal catalytic material for electrochemical sensors due to their large specific surface area and good catalytic activity,which are widely used in the fields of glucose,DNA,protein and tumor markers.In this thesis,different MOF-based Au/PDMS-based integrated electrochemical sensors were constructed with Polydimethylsiloxane(PDMS)as the substrate material,gold nanoparticles formed as the conductive material and MOF as the catalytic material,and their applications in the detection of disease molecules were investigated.The three parts of the study are as follows:Part one Ni-Co MOF-based integrated Au/PDMS-based electrochemical sensor for real-time detection of glucose in human sweatAn integrated electrochemical sweat sensor based on Ni-Co MOF nanosheets coated with Au/PDMS films was prepared for the highly sensitive continuous monitoring of glucose levels in sweat.First,a triple electrode based on a stretchable Au/PDMS film was prepared by chemically depositing a gold layer on hydrophilictreated PDMS.Then,Ni-Co MOF nanosheets with high electrocatalytic activity were synthesized by a facile solvothermal method and modified on the Au/PDMS electrode as a working electrode.Ni-Co MOF/Au/PDMS(NCAP)thin film electrode exhibited excellent electrochemical performance for glucose detection with a wide linear range of 20 μM to 790 μM and a sensitivity of 205.1 μA mM-1 cm-2.In addition,the sensor still showed high stability and good electrochemical response to glucose when stretched and bent to different degrees.In addition,it maintained long time stability and high selectivity for glucose monitoring.Finally,the working area of the sensor was covered with a sweat-absorbent cloth and secured with stitches to form an integrated sweat glucose sensor.The sensor can be attached to the skin for stable,accurate,and continuous monitoring of glucose levels in human sweat.This work validates the potential of our integrated electrochemical sensor for applications in extraclinical health monitoring.Part two Construction of label-free integrated Au/PDMS-based electrochemical aptamer sensor for exosome detection based on Cu MOFA Cu MOF-based label-free immunosensor was prepared for the quantitative detection of exosomes.The Au/PDMS electrode was prepared by a simple chemical deposition method.Amino-functionalized Cu MOF was synthesized as an electrochemical immunosensing material by a simple solvothermal method using copper nitrate and diaminoterephthalic acid.Cu MOF was coupled with streptavidin(SA)and modified onto the surface of the Au/PDMS electrode,and the biotinylated PD-L1 aptamer was bound to Cu MOF for exosome capture through the strong interaction of biotin(Biotin)and SA.When exosomes were captured by the sensor electrode,the immune complex formed greatly reduced the catalytic performance of Cu MOF,which led to a significant reduction of the electrochemical signal on the electrode surface,thereby enabling quantitative detection of different concentrations of exosomes.The electrochemical immunosensor prepared by this scheme shows great significance in the early diagnosis of diseases.Part three Integrated Au/PDMS-based electrochemical immunosensor based on Fe-Co MOF signal amplification for AFP detectionAn integrated electrochemical immunosensor was fabricated based on Au/PDMS with Fe-Co MOF as the signal amplification tag for ultrasensitive determination of alpha-fetoprotein(AFP).First,a gold layer was deposited on a hydrophilic PDMS membrane to form a flexible three-electrode system,followed by immobilization of the thiosubstituted aptamer of AFP.Subsequently,aminated Fe-Co MOF with high peroxidase-like activity and large specific surface area was prepared by a simple solvothermal method,and subsequently biofunctionalized MOF could effectively capture biotin antibody(Ab)to form MOF-Ab as a signal probe and significantly amplify the electrochemical signal,resulting in a highly sensitive detection of AFP with a linear range of 0.01-300 ng/mL.In addition,the PDMS-based immunosensor showed good accuracy for the determination of AFP in clinical serum samples.The integrated flexible electrochemical immunosensor based on Fe-Co MOF as a signal amplifier shows great potential for application in clinical rapid detection.