Aggregation Induced Emission Molecules Based On Triphenylamine For The Detection And Sterilization Of Pathogenic Bacteria

Aggregation-induced luminescent molecules possess excellent photobleaching resistance,biocompatibility and high emission intensity,which can fundamentally solve the problem of aggregation-induced quenching that is easy to occur in traditional organic fluorescent molecules.The rise of AIE fluorescent materials provides a new choice for analytical detection,biological imaging and other fields.Among them,triphenylamine,as the classical skeleton of AIE,is easy to introduce a variety of functional groups to synthesize a wide variety of triphenylamine derivatives.In this thesis,we have designed and synthesized two kinds of triphenylamine-based AIE molecules for pathogenic bacteria detection and photodynamic killing.The specific research content is as follows:1.A triphenylamine derivative TPA-OH with o-hydroxybenzaldehyde structure was designed and synthesized,which had excited intramolecular proton transfer（ESIPT）and AIE properties.The probe TPA-gal was further synthesized by introducing a specific recognition group ofβ-galactosidase on the hydroxyl group of TPA-OH molecule,thus the ESIPT process was blocked.TPA-gal specifically recognizedβ-galactosidase and was hydrolyzed to TPA-OH.The ESIPT process resumed and the system showed fluorescence turn-on phenomenon.The fluorescence intensity of the system had a good linear relationship withβ-galactosidase in the range of 5-250 U/L and 250-1000 U/L,respectively,and the detection limit was as low as 3.64 U/L.More importantly,phage coupled magnetic beads（p MBs）were used to isolate,enrich and lyse E.coli O157:H7 to releaseβ-galactosidase,thus achieving specific quantitative detection of E.coli O157:H7.This method could also effectively reduce the influence of detection matrix,and was successfully used for the quantitative detection of 10-10⁶ CFU/m L E.coli O157:H7 in water samples and milk samples.The fluorescence intensity of the system had a good linear relationship with the logarithm of the concentration of E.coli O157:H7.The probe TPA-gal was easy to prepare,possessed good selectivity,sensitivity and practical sample detection ability.2.TTQ-PF₆,an AIE molecule based on triphenylamine backbone,was designed and synthesized.This compound was characteristic of a strong D-π-A structure,a large Stokes shift,and effectively produced reactive oxygen species.TTQ-PF₆ was successfully used for photodynamic anti-bacterial treatment.The anti-bacterial effect was verified by scanning electron microscopy,and selective bacterial fluorescence imaging was achieved to a certain extent.In addition,MTT assay showed that TTQ-PF₆ had low toxicity to mouse macrophage Raw cells,and thus a mouse model of MRSA infection was established.Mice（relative wound area～10%）treated with TTQ-PF₆ photodynamic therapy recovered faster than that（relative wound area～13%）treated with the MRSA antibiotic vancomycin,showing excellent antibacterial activity in vivo.AIE molecules based on triphenylamine backbone have been designed and synthesized using different principles,and all of them show excellent photophysical properties.They have been successfully used as fluorescent probes for enzyme activity,bacterial detection and photodynamic anti-bacterial materials,which provide a good basis for their application in analytical detection,biomedicine and environmental medicine.