Study On Electrochemical Aptamer Sensors Based On Porous Organic Frameworks Containing Porphyrin And Synthesis And Properties Of Novel Organic Optical Chromophores

Porous organic porphyrin materials combine the advantages of porous organic materials and porphyrin compounds.They have both adjustable pore sizes and multifunctional binding sites.Metal nanoclusters have catalytic properties similar to enzymes.In this paper,porous organic porphyrin materials and metal nanocluster materials were synthesized as probes to construct biosensors to achieve the detection of targets.Organic non-linear chromophores G1-G4 with high electro-optic coefficients were synthesized to provide application options for optical materials.?1?A H₂O₂ sensor was constructed using Nafion?perfluoropolystyrene sulfonic acid solution?-ZnP?Zn Porphyrinic?-CTF?covalent triazine frameworks?complex.First,a ZnP-CTF material was prepared,and gold nanoparticles were incorporated therein to obtain an Au NPs@ZnP-CTF composite material.A hydrogen peroxide sensor was prepared by mixing Au NPs@ZnP-CTF with a 5%Nafion solution and modified on the surface of a glassy carbon electrode.Cyclic voltammetry and chronoamperometry were used to investigate the catalytic effect of modified electrodes on hydrogen peroxide.The results show that this material has a good catalytic effect on the reduction of hydrogen peroxide.When the concentration of hydrogen peroxide is in the range of 0.48⁹0.9 mmol/L,the response current of the electrode has a good linear relationship with the concentration of hydrogen peroxide,and the detection limit is 0.1 mmol/L.The sensor has a wide linear range and good selectivity.?2?An aptamer sensor based on covalent triazine frameworks material was constructed to detect ochratoxin?OTA?.Covalent triazine-based organic framework loaded with Au nanoparticles composite?Au NPs@ZnP-CTF?was firstly prepared and then coupled with streptavidin?SA?as signal probe to label OTA aptamers?S2?modified with biotin.The single strand DNA?S1?partially complementary to the aptamer of ochratoxin?OTA?was immobilized with Au NPs@Co MOF composite as the immobilized matrix through Au-SH bond,and aptamer of OTA?S2?was combined through hybridization.The catalytic current signal of the label to the reduction reaction of hydrogen peroxide was determined by chronoamperometry.When OTA was introduced,the aptamer chain was specifically combined with OTA,dissociated with S1,which resulted in the catalytic current decreasing,so as to realize the quantitative measurement of OTA.?3?A signal-off aptasensor was constructed based on the specific binding characteristics of OTA and OTA aptamer?DNA2?to detect the small molecule ochratoxin A?OTA?.DNA1 chain with mercapto modified at 3'-end was firstly immobilized on the surface of gold electrode,which can partial complementary hybridize with DNA2-strand to form double strands.30 thymine T modified at the end of DNA2 were used as templates to synthesize Cu NCs which is peroxidase mimics and can catalyze the reduction of hydrogen peroxide.In the presence of OTA,it specifically binds to DNA2,which made DNA2 dissociated from the surface of gold electrode,and so did Cu NCs.With the increase of OTA in solution,aptamers and Cu NCs dissociated from the gold electrode increased,which resulted in the less copper nanoclusters remained on the electrode,and the decreasing of the response current value of the electrode measured by chronoamperometry.Thus,the quantitative determination of OTA can be achieved.This aptasensor provides a simple and fast technique for OTA detection in red wine samples.?4?Four chromophores G1-G4 with bis?N,N-diethyl?aniline derivatives as donors were designed and synthesized,and optically introduced on isophorone-derived electron bridges of chromophores G3 and G4 receptive group of a reactive aniline derivative.At 25 wt%doping concentration,chromophores G3 and G4 achieved 226pm/V and 215 pm/V electro-optic coefficients,which are much higher than 169 pm/V and 156 pm/V of chromophores G1 and G2 without the introduction of optically active spacer groups is also much higher than similar doping systems.