Electrochemical Preparation Of Nanoporous Conducting Polymers And Their Catalytic And Sensing Application

In recent years,nanoporous conducting polymers show great potential in sensing fields,owing to their innate merits of tunable redox performances and outstanding environmental stability.This thesis fabricated novel chemical and biological sensors,based on nanoporous conductive polymers loaded with metal nanoparticles modified electrodes,for the high-sensitive detection of disease related markers,which lays the foundation for the early diagnosis and treatment of disease.The main contents of this thesis are summarized as follows:(1)Three-dimensional(3D)nanoporous poly(3,4-ethylenedioxythiophene)(PEDOT)was electrochemically prepared using a hard-template method and Cu nanoparticles(Cu NPs)were further loaded into the porous PEDOT nanostructure through electrodeposition.As the 3D nanoporous PEDOT possesses a large surface area and is highly stable and conductive,it provides an excellent substrate for the loading of a large amount of CuNPs.The prepared porous CuNPs/PEDOT nanocomposite exhibited an excellent electrocatalytic property toward the oxidation of glucose owing to its unique microstructure,where the loaded Cu NPs provide many active sites for the oxidation of glucose,and the 3D porous structure can facilitate the diffusion of glucose molecules and accelerate the electron transfer.Under optimal conditions,the porous nanocomposite modified electrode displayed a wide linear range for glucose detection from 0.1 to 482.1 ?M,with a detection limit of 52 nM.The sensitivity of the glucose sensor(329.6 ?A/mM/cm2)was about 8 times higher than that of the electrode modified with Cu NPs on planar PEDOT.All the above results indicated that significant enhancement effect has been achieved by the 3D nanoporous structure.(2)Three-dimensional(3D)nanoporous polyaniline(PANI)doped with poly(sodium 4-styrene sulfonate)(PSS)was electrochemically prepared by using a hard-template method.The 3D nanoporous PANI possessed large surface area,high conductivity and many functional groups,therefore,it provides an excellent substrate for the immobilization of alpha-fetoprotein(AFP)antibodies to construct an electrochemical biosensor.Based on the measurement of the inherent redox signal change of the porous PANI,the prepared AFP immunosensor was redox reagentless and exhibited satisfying sensing performances toward its target AFP.Under optimal conditions,the porous PANI-based immunosensor achieved a wide linear range for AFP from 0.01 to 1,000 pg/mL,with a detection limit of 5.3 fg/m L(S/N = 3).Significantly,the response sensitivity of this sensor was about 2 times higher than that of the planar PANI-modified electrode,manifesting a great enhancement effect associated with the 3D nanoporous structure.(3)Three-dimensional(3D)nanoporous poly(3,4-ethylenedioxythiophene)(PEDOT)doped with poly(sodium 4-styrene sulfonate)(PSS)was electrochemically prepared by using a hard-template method,and Au nanoparticles(AuNPs)were further loaded into the porous PEDOT nanostructure through electrodeposition.The 3D nanoporous PEDOT possessed large surface area which could load a large amount of AuNPs.The thiol-modified capture probe(P1)was firstly immobilized onto Au substrate surface through Au-S bonds,and thus biosensors capable of sensing breast cancer susceptibility gene BRCA1 were obtained.Under optimal conditions,the porous PEDOT-based DNA biosensor achieved a wide linear range for BRCA1 from 1.0 fM to 0.1 nM,with a detection limit of 0.67 fM(S/N = 3).The constructed DNA biosensor exhibited good sensitivity and selectivity,indicating its promising applications in biosensing field.