Novel Porous Organic Polymers:Synthesis,Characterization And Design Of Bio-immunosensors

So far,porous materials have developed from inorganic materials to organic materials,from small molecules to polymers,from a single material to composite materials.Thus,porous materials have been traversed throughout the field of materials chemistry.Porous organic polymer(POP)materials,as a new and young member of the porous material family,have been rapidly involved in the fields of gas adsorption and separation,heterogeneous catalysis,biochemical sensing,and optoelectronic materials under the extensive attention and research of researchers.Among the POP materials,covalent organic framework materials(COFs)have both ordered pore structure and good crystallinity.Amorphous covalent organic polymer materials(COPs)have a high specific surface area,easy to modify the pore structure,super thermal stability and chemical stability,causing a wide range of research boom.In view of these two point,a new kind of covalent organic polymer material(named FePor-TFPA-COP)was designed and synthesized in this paper.In this paper,a novel covalent organic polymer material(named FePor-TFPA-COP)and a novel covalent organic framework material(named D-T-COF)were sythesized and characterized by various methods,and their properties were systematically studied.Two types of bioimmune sensors were designed and used for quantitative detection of a-fetoprotein.The paper discusses two aspects of the work:In Chapter 2,we synthesized a cost-effective porphyrin based covalent organic polymer,namely FePor-TFPA-COP,through an easy aromatic substitution reaction between pyrrole and tris(4-formylphenyl)amine(TFPA).The triangular pyramid shaped,N-centric structure of TFPA facilitated the formation of FePor-TFPA-COP with three-dimensional porous structure,larger surface area and abundant surface catalytic active sites.FePor-TFPA-COP exhibited strong intrinsic peroxidase activity toward a classical peroxidase substrate 3,3',5,5'-tetramethylbenzidine(TMB)in the presence of H2O2.Compared with Horseradish peroxidase(HRP),FePor-TFPA-COP exhibited several advantages such as easy storage,high sensitivity,and prominently chemical and catalytic stability under the harsh conditions,which guaranteed the accuracy and reliability of measurements.Utilizing the excellent catalytic activity,a FePor-TFPA-COP based colorimetric immunoassay was first established for AFP detection and showed high sensitivity,stability and acceptable reproducibility.The linear responses range for AFP was 5 pg/mL to 100 ng/mL and the detection limitation is 1 pg/mL.The routine provided a brilliant biomimetic catalyst to develop the non-enzyme immunoassay.More importantly,the high chemical and catalytic stability and sensitivity facilitated the future practical applications under various conditions.In Chapter 3,we describe the synthesis of a new COF material,named as D-T-COF,based on 2,6-dihydroxynaphthalene-1,5-dicarbaldehyde(DHNDA),serving as an electron donor building block and 1,3,5-Tris(4-aminophenyl)benzene(TAPB)as an electron acceptor building block in a covalent organic framework through a facile solvothermal method,and characterize the structure and morphology by different methods.To overcome the disadvantage of COFs that they are poorly soluble and difficult to be processed into devices,we adopt the strategy of in-situ growth,that is to introduce our COF material to grow on ITO substrates for ease of study of the PEC property of the COF film.In virtue of excellent photocurrent signals,we design a simple label-free PEC immunosensor for detecting concentration of AFP.The immunosensor is fabricated by layer-by-layer coating D-T-COF,chitosan(CS),glutaraldehyde.(GA)composite on the COF-ITO as the working electrode.The introduction of CS brings the COF material better biocompatibility and film-forming properties,and the rich amino groups of CS modified on COF film offer great convenience to assemble GA cross-linker for expanding the surface area to capture a large number of AFP antibodies(Ab)as well as improving the stability of the electrode surface.The proposed PEC immunosensor provides a useful tool for detecting AFP,which exhibited acceptable specificity,sensitivity,experimental reproducibility and stability.