Novel Porous Organic Polymers Nanozymes:Synthesis,Characterization And Applications Of Bacterial Detection And Elimination

It is well known that wound infections and food poisoning caused by Staphylococcus aureus(S.aureus)still pose a serious threat to human health.It is still challenging to develop a new multi-functional material that can detect bacteria sensitively,and can sterilize efficiently without drug resistance.Since their birth,nano-enzymes have attracted the attention of scientific researchers because of their unique properties of mimic enzymes.The researchers drew inspiration from the natural immune system,and designed and constructed specific nanoenzymes to convert H2O2 into highly biologically toxic reactive oxygen species(ROS,including ·OH),thereby giving nanozymes the ability to inhibit bacterial survival.However,the nano-enzyme antibacterial agent sterilized by a single enzymatic performance has the disadvantages of poor catalytic performance under neutral conditions,and cannot effectively catalyze the production of ·OH with low concentration of H2O2.It is gratifying that the multi-mode antibacterial strategy of nano-enzyme synergy largely solves the above problems.Porphyrin-based porous organic polymers(PPOPs),a new type of nano-enzymes,has attracted extensive attention from scientists because of their large surface area,adjustable pore structure,excellent stability,and excellent enzymatic and optical properties.However,as far as we know,the research on PPOPs nano-enzymes that combine enzymatic properties and optical properties as fungicides and bacteria detection agents has not been widely reported.Based on this,this paper reports a new bifunctional porphyrin-based porous organic polymer FePPOPBFPB,systematically studied its performance,and explored its application in the elimination and detection of bacteria.The specific research contents of the thesis are as follows:1.A new porphyrin-based porous organic polymer,FePPOPBFPB,was synthesized via the reaction between pyrrole and 4-{2,2-bis[(4-formylphenoxy)methyl]-3-(4-formylphenoxy)propoxy} benzaldehyde(BFPB).The C-centric tetrahedral structure of BFPB promoted the formation of FePPOPBFPB with a 3D interconnected porous structure,high specific surface area,and plentiful surface catalytic active sites.FcPPOPBFPB exhibited excellent peroxidase-like activity toward a representative peroxidase substrate,3,3',5,5'-tetramethylbenzidine(TMB)with H2O2,Furthermore,the adjustable structural alkyl chain also enhanced the absorption capability of FePPOPBFPB in the long-wavelength visible and near-infrared regions(NIR).2.Based on the above satisfactory features,we examined the bactericidal properties of FePPOPBFPB against S.aureus under near-infrared light radiation,and explored FePPOPBFPB possible antibacterial mechanisms by examining the main reactive oxygen species(ROS)components produced in the antibacterial system.The combination of enzyme-like catalytic properties and near-infrared light(NIR)absorption properties,FePPOPBFPB can effectively catalyze the H2O2 of physiological concentrations(100 p.M)decomposition at neutral conditions to produce a large number of ·OH that can effectively kill bacteria and form a light-fenton antibacterial mode,thus avoiding the extensive use of exogenous H2O2.3.By utilizing its superior peroxidase activity,rapid and visible detection of S.aureus based on FePPOPBFPB was first established with acceptable specificity,sensitivity,and stability.S.aureus could be directly analyzed within a linear range of 102 to 107 CFU/mL with a detection limit(LOD)of 24 CFU/mL(S/N=3).