Near-Infrared Fluorescent Dyes Based On Rhodamine Derivatives: Design,Systhesis And Applications In Bioimaging

Fluorescence bioimaging has been widely used in basic biological research and clinical diagnosis due to its numerous outstanding advanteges,such as high sensitivity,non-invasive,real-time and low cost.The near-infrared(NIR)bioimaging technology has became an important research direction of fluorescence bioimaging,because it can reduce the interference of the auto-fluorescence of the biological samples,improve the penetration depeth,reduce the optical damage.The development of NIR bioimaging technology is inseparable from the support of NIR fluorescent probe.Small molecule fluorescent probe with high molar extinction coefficients and fluorescence quantum yield,easy-adjustive molecular structure and spectral range,good biological compatibility,which has attracted the sustained attention.However,the reported NIR dyes always processed the shortcoming of poor lignt-stability and water-quenching luminescence,and their functions and spectral range can not meet the demand in practical application.Therefore,the design and synthesis of NIR fluorescent dyes with excellent photophysical properties has important research significance.In this thesis,we choose the NIR rhodamine dye as the research direction.A series of fluorescent dyes with excellent photophysical properties were designed and synthesized,which have precisely-controlled absorption and emission spectra.And their applicability in molecular sensing and biological imaging was studied.Finally,through the combination of the properties of the NIR dyes and various luminescence imaging technologies,the application of biological detection and imaging with more sensitivity and accuracy is realized.The research content of this thesis includes the following parts:1.Design,synthesis and regulation wavelength of rhodamine-based NIR fluorescent dyesA series of NIR fluorescent dyes based on rhodamine dericatives were designed and synthesized using the optimized methods.Through the structure expansion and spectrum abjustment,we obtained NIR dyes with large molar extinction coefficient and fluorescence quantum yield,and the NIR absorption and emission could cover 650-1000 nm region.This method of spectrum regulation of rhodamine dyes provided reference for the design and synthesis of more NIR organic dyes.2.Design and synthesis NIR rhodamine probes and its application in bio detection and bioimaging in vivoUtilizing a general synthetic method developed by our group,we obtained a series of NIR fluorescent probes based on rhodamine derivatives.The application of these rhodamine probes in molecular sensing,biological detection,and bioimaging in vivo were studied through spectral test.bioimaging in living cells and in vivo.And this also provided the design idea and synthetic method for more NIR probes with the application in biodetection and bioimaging.3.Upconversion luminescent chemodosimeter based on NIR organic dye for monitoring methylmercury in vivowe have constructed a NIR upconversion luminescence MeHg+ chemodosimeter FUC-1 based on frequency upconversion luminescence mechanism by a design strategy of using the thiospirolactone interactions between Hg and S.FUC-1 exhibited the amazing FUCL,excellent NIR fluorescence enhancement,high selectivity and low limit of detection for mercury.Furthermore,we can use this FUCL probe FUC-1 for monitoring mercury ex vivo and in vivo by both Stokes luminescence and upconversion luminescence bioimaging,The design strategy for FUCL-based probes in this work will lead to a new generation of probes for specific analytes for promising application in biosensing and bioimaging in vitro and in vivo.4.A chromophoric dyad as ratiometric luminescent and lifetime-based probe for monitoring hypochlorite in vitro and in vivoWe have described a new design strategy to construct a chromophore dyad as ratiometric and lifetime-based probe for hypochlorite based on Forster resonance energy transfer.The energy donor is a phosphorescent iridium(?)complex and the acceptor is a NIR fluorophore,connecting with a covalent bond.This ratiometric and lifetime-based luminescence probe could be used for monitoring CIO-in aqueous solution with high sensitivity.The utilization of this probe to detect intracellular exogenous and endogenous CIO-has been demonstrated via ratiometric imaging and PLIM.In addition,with the long wavelength emission,Ir-NIR has been successfully applied to image CIO-in inflammation mouse model.5.Photostable fluorescent probe based on NIR Rhodamine derivative for biosensing and bioimaging in vivoA new kind of NIR organic dye(Rho-650)based on rhodamine derivatives was synthesized,which has large molar extinction coefficient and fluorescence quantum yield and better photo stability in water.The fluorescent probe Rha-650-Cu,which was obtained by Rho-650 functional modification,has well response to Cu2+ in vitro and in vivo.Through the combiantion of the probe Rho-650-Cu and lanthanide doped upconversion nanoparticles(UCNPs),this water-soluble nanosensor was successfully used in ratiometrical upconversion luminescenct biosensing and bioimaging of Cu2+ in living cells and living animals.