Ultraviolet And Electrochemical Analysis Methods Based On Metal-organic Framework Materials For Detection Of C-reactive Protein And Hydrogen Sulfide

The nanoporous material sensor is a sensing technology that combines photoelectrochemistry,nanomaterials,and biological detection technology for analytical detection.At present,nanoporous materials have the advantages of large specific surface area,large proportion of surface atoms,and controllable composition and morphology.Thus,nanoporous materials-based biosensors have widy applied in the aspects of analytical chemistry,such as the detection of biomarkers and toxins in production and life.In this thesis,a series of nano-porous materials with large specific surface area,excellent electron transport performance,and low cost of raw materials were synthesized,includingthe three materials,perylene diimide derivative（PDI）,polyaniline（PANI）,and carboxylated carbon nitride（C₃N₄）composite materials（PDI-PANI-C₃N₄）and three different metal-organic framework materials（MOFs-Cd-MOF-74,Cu（Ⅱ）-HKUST-1 and Co/Fe-MOFs）.Then,those nano-porous materials were used to construct electrochemical and visual colorimetric sensors,respectively.The specific work is as follows:（1）In this work,composite material PDI-PANI-C₃N₄ were synthesizedvia the three materials（PDI,PANI,and C₃N₄）,which are polymerized by electrostatic interactions with positive and negative charges.Using this composite as an electrochemically active substance and substrate,a non-labeled immunosensor was constructed for the quantitative detection of C-reactive protein（CRP）.This sensor can detect CRP directly in PBS（pH 7.4）using differential pulse voltammetry（DPV）without adding other electroactive substances to the solution.When CRP antibody and antigen was specifically combined to the electrode surface,which can block the interfacial electron transfer.Its response current will decrease with the increase of the bound CRP antigen.Thereby,the sensor could be empoyed for the real-time and rapid detection of CRP.These label-free biosensor has a linear range of 5-200 ng/mL.And the detection limit of 1.66 ng/mL was obtained.（2）In the second chapter,a rod-shaped material Cd-MOF-74 was synthesized,which has a peak current response at-0.8 V in the DPV detection.Thus,Cd-MOF-74was utilizedas signal label,and Au NPs@C₃N₄ was used as fixed substrate.A novel sandwich-type immunosensor was constructed for the quantitative detection of CRP.The response current intensity increases linearly with the increase of CRP concentration,and the biosensor liner range is between 0.1-100 ng/mL.The detection limit is 33.33 pg/mL by 3σrule.In addition,the detection limit of the proposed sandwich sensor in this chapter is 3 orders of magnitude lower than that of a standard kit.（3）Hydrogen sulfide（H₂S）is involved in a variety of pathophysiological processes.The detection of H₂S is of great significance in revealing its role in the diagnosis of various diseases.Chapter 4 presents a method for the quantitative detection of H₂S.Iodide ion（I^-）could improve the catalytic activity of bimetal porous materials Co/Fe-MOFs.While,HS^-inhibits the catalytic performance of Co/Fe-MOFs-I^-.The detection solution exhibited distinct color changes from deep blue to light blue.This experiment compares the sensitivity of the Co/Fe-MOFs-H₂O₂-TMB system before and after I^-addition.The results show that the linear range is 1 nM-100μM,and R²=0.992.The detection limit is 2 orders of lower than that of system that I^-is not added.The method has achieved satisfactory results in the detection of spikes in serum samples.（4）Chapter 4 constructed a colorimetric biosensor for iron ions(Fe³⁺)using Cu-MOFs（Cu（Ⅱ）-HKUST-1）.The porous structure of Cu-MOFs with three-dimensional structure have a large number of active sites,which could provide a wealth of sites for I^-,laying a foundation for improving the catalytic effect of Fe³⁺.After the addition of Fe³⁺,the intensity of the UV absorption peak at 650 nm of Cu-MOFs-I^--TMB system increases linearly with the increase of Fe³⁺concentration（1-1000μM）.The detection limit is 333.33 nM.The colorimetric biosensor has been applied to the detection of Fe³⁺in Dianchi water samples.