The Exploration Of Planar Aiegen And Its Applicatopn For Mdr Bacteria Treatment

Aggregation-caused quenching(ACQ)remains a significant limitation of traditional organic fluorophores.Especially,most planar luminogens encountered difficulties in overcoming intrinsic ACQ effect by intermolecular ?-? stacking interactions in the aggregation state.The emergence and development of aggregation induced emission(AIE)has offered a great opportunity to overcome this bottleneck.For example,excited-state double-bond reorganization(ESDBR)can guide us on designing planar aggregation-induced emission luminogens(AIEgens),but its mechanism has yet been elucidated.Major challenges in the field include methods to efficiently restrict ESDBR and enhance AIE performance without using bulky substituents(e.g.,tetraphenylethylene and triphenylamine).In addition,with the development of biomedicine,more and more research and applications require materials with richer functions,which will outperform the performance of materials with single function in complex scenes.Therefore,it remains an urgent need to explore additional characteristics of fluorescent materials,providing advanced technical solutions for biomedical research and clinical translation.In this study,we designed and developed a series of fluoro-substituent AIEgens with stronger intermolecular H-bonding interaction for restricted molecular motions and increased crystal density,leading to one order of magnitude of decreased in nonradiative decay rate.The molecule with adjusted ESDBR properties also show a corresponding response to variation in viscosity.Furthermore,their ability of aggregation-induced reactive oxygen species(ROS)generation has been discovered.We further applied this AIEgens in antimicrobial photodynamic therapy(a PDT).In the in vitro study,we thoroughly investigated the killing efficiency of the materials against MDR E.coli and MRSA.The results suggest that the AIEgen-based photosensitizer can effectively kill the MDR bacteria in a short time while showing negligible toxicity to the normal mammalian cells.In order to verify the therapeutic effect of the material on the living body,we successfully designed and constructed a three-degree burn infection model in mice through multi-drug resistance infection,and comprehensively evaluated the performance of this plane AIEgen through wound measurement,bacterial quantification and histological observation.Through this study,the relationship between ROS generation and distinct E/Z-configurational stacking behaviors have been further understood,providing a design principle for synthesizing planar AIEgens-based photosensitizers.In addition,through in vitro and in vivo experiments,it has laid a solid foundation for plane AIEgens to be used in a PDT,further widened its application scope in biomedical field,and opened a new door for exploration and application of advanced AIEgens.