Preparation Of Silicon-containing Polymer Fluorescent Materials And Their Applications In Cell Imaging

Fluorescence spectrometry is widely concerned for its advantages of low pretreatment requirements,simple operation,good targeting,fast detection speed,high sensitivity and convenient portability.Compared with small molecule fluorescent probes,polymer fluorescent materials have special properties and applications,such as stable main chain structure and good modification,good biocompatibility,good photostability,and can be made into optical devices.More importantly,the sensors based on polymer materials have the characteristics of signal amplification which can detect ions or biomolecules at ultra-low level.And there are many polymer recognition sites,which improves the specific recognition and binding efficiency of analytes.Silicon atoms and Si-O bonds have unique properties and the introduction of Si and Si-O bonds can make the polymer materials have more excellent properties.The 3d space orbits of silicon atom can be used to form d?-p?coordination bond,and silicon atom can be hybridized with other atoms.The Si-O bonds have a low rotation barrier,so introducing silicon atom into the main chain of conjugated polymer can reduce the rigidity of the main chain.The higher bond energy of Si-O bonds enable silicon containing polymer have better thermal stability.In addition,the side chain of silicon-containing polymer can be functionalized by introducing specific groups,so that the polymer has more specific properties and can be utilized as a multi-substitutional functional material.In this thesis,a series of silicon-containing polymer fluorescent materials were synthesized by the thiol click reaction and Heck coupling reaction.Their optical properties and their applications in analyte detection and cell imaging were studied.1.Using trimethylsilylacetylene and dithiol as raw materials,a series of silicon-based polythioethers with unconventional fluorescence were synthesized by successive thiol click reaction.Although there is no rigid?-conjugation structure in the polymer chain,polythioethers had visible blue fluorescence in the solution and displayed outstanding fluorescence properties in living cells.In addition,the response of different polythioethers to metal ions showed that terminal modification with different sulfhydryl compounds can improve the selectivity of polythioethers to Fe³⁺.This work further discussed their application in cell imaging and their response to Fe³⁺in living cells.The synthesis route in the study is expected to be extended to the synthesis of novel polythioethers with outstanding optical properties.Their applications in ion detection and cell imaging will enlarge the utilization of polythioethers.2.Under ultraviolet light at ambient temperature,the silylvinyl-terminated polythioethers(P1 and P2)was prepared via thiol-alkyne click reaction.The vinyl polythioethers was modified with mercaptoethyl rhodamine lactam(RB-SH)through the click reaction to obtain functionalized polythioethers fluorescent materials(P1-RB and P2-RB).The silicon-containing polythioethers material exhibited visible fluorescence in solution and had good selectivity and response to Fe³⁺,and the minimum detection limit is 2.77?M.Polythioethers can also be applied for fluorescence imaging in cells.The polymer modified with RB-SH can displayed fluorescence in blue and red channels,and can be used to monitor the changes of Fe³⁺concentration in cells sensitively.It showed that polythioethers based fluorescent probe has a broad application prospect in ion detection and biological imaging.3.Pyrene-based polymers(Py M and Py P)with linear and network structure were prepared by modifying pyrene fluorescence group on polysiloxane chain by heck coupling reaction.The prepared polymer material has bright blue fluorescence in the solution,and the quenching percentage after adding 2,4,6-trinitrophenol(TNP)is as high as 95.2%,indicating that the pyrene-based polymer has high selectivity and sensitivity to TNP.On this basis,a portable paper sensor for TNP detection was developed for rapid on-site detection.In addition,the obtained fluorescent material can be further applied to cell imaging.The construction strategy of fluorescent materials involved in this work provided new ideas for the design of fluorescent sensors for nitroaromatic explosives.