Design,Synthesis And Application In Cell Imaging Of AIE Functional Molecules Based On Tetraphenylethylene

Aggregation induced luminescence（AIE）materials,as a new class of smart materials,have unique optical properties and good biocompatibility.At present,it has been widely used in many fields,such as chemical sensing,smart nanomaterials,bio-optical imaging and other fields.Among them,tetraphenylethylene（TPE）is called the"star molecule"in the aggregation-induced emission molecules,and has been widely researched and applied since its discovery.In order to expand the application field of TPE,this paper aims to develop several new AIE functional fluorescent material molecules based on TPE.The AIE phenomenon is extended to the ion-adjustable one-dimensional/two-dimensional nano-assembly system,and the conversion of the one-dimensional fiber assembly with AIE performance into a two-dimensional sheet assembly is realized.Combining a group with ion-responsive properties and an AIE group through a simple preparation process,several functional material with low biological toxicity and environmentally-sensitive response properties is synthesized,which can be applied to the fields of bioimaging and organic optoelectronics.We systematically studied the molecular structure,optical properties,response characteristics,self-assembly behaviors and cell imaging effects of these materials.The details are as follows:1.Study on the construction and optical properties of ion-regulated 1D/2D nano-assembly based on tetraphenylethyleneIn the first part,we designed and synthesized two novel amphiphilic fluorescent materials containing TPE groups:TPE-ON and TPE-ONS.The self-assembly morphologies of the two above the critical micelle concentration were measured by electron microscopy,and their optical characteristics were studied by spectral analysis techniques.The experimental results showed that:（1）By changing the counter ions of the molecule,the conversion from a 1D fiber assembly with AIE properties to a 2D sheet assembly has been achieved.（2）After the assembly of TPE-ON and TPE-ONS,the fluorescence intensity of TPE-ONS was 2.3 times that of TPE-ON and remains unchanged.（3）When TPE-ON contains different proportions of TPE-ONS,as the TPE-ONS content increases,there was a certain correlation between the two:Y=2113.71+5163.56x-2966.07x².This correlation can be used to detect counterbalances ion conversion process.This investigation provides a new method for the synthesis of novel fluorescent molecular materials,and lays the foundation for the applications of assembly materials with controlled morphologies to optical devices,fluorescent sensors,fluorescent biological probes,and other aspects.2.Synthesis of a novel zinc ion fluorescent molecular probe based on tetraphenylethylene and its application in cell imagingIn the second part,we designed and synthesized a fluorescent probe molecule TPE-3N based on the combination of bis（2-pyridylmethyl）ammonia（DPA）.Spectral studies have shown that TPE-3N can specifically recognize Zn²⁺in the common metal ions.TPE-3N was not sensitive to pH and can recognize Zn²⁺in a fairly wide range.Cytotoxicity test results showed that the cell viability was above 85%,indicating that the molecule has low toxicity.We compared TPE-3N with zinc ion to TPE-3N without zinc ion.The experimental results show that TPE-3N can enter the cell well,and the fluorescence signal was more obvious in the cell after adding zinc ion.The effect of adding zinc ion in the cell was better.As a kind of excellent AIE fluorescent probe,the molecule is expected to have applications for the detection of free zinc ions selectively in the body of organism.3.Preparation of pH-responsive polymer fluorescent nanomaterials based on tetraphenylethylene and their applications in cell imagingIn the third part,we used the TPE as the luminescent group to prepare S-TPE-PAA and D-TPE-PAA polymers through condensation reactions.We studied their optical characteristics by spectral analysis techniques,and scanned electron microscopy.The self-assembling morphologies were determined by scanned electron microscopy,as well as their cytotoxicity and cell imaging effects were obtained using fluorescence microscope（test instrument）.The results show that these two types of AIE polymers are sensitive to pH.And it can self-assemble in water to form nano-sized spheres and flower-shaped assemblies.Both have low toxicity to cells.By comparing the imaging effects in cells,S-TPE-PAA has a better imaging effect in cells.It is expected to develop applications in cell imaging and tracing.D-TPE-PAA has good pH response characteristics and can be used as a pH sensor for detection of the environment,water quality and other fields.