Design,Synthesis,Characterization Of Original Fluorescent Dyes And Their Applications In Biological Research

Fluorescent dyes are widely used in modern biomedical research such as invitro or in vivo imaging,photoacoustic tomography,photothermal ablation,photodynamic therapy etc.Therefore,development of high-performance fluorescent dyes and other fluorescent molecular tools is an important research area.In this paper,we developed a range of dyes,including infrared fluorescent dyes,sterically protected stable xanthene dyes,long wavelength emitting two-photon dyes,crossed two-dimensional dyes and series of sensing dyes.Light of long wavelength scatters less and penetrates deeper in biological tissue.Therefore,long wavelength dyes are advantageous in living imaging or therapy.However,there is a lack of infrared fluorescent dyes with high stability and high dispersibility.This paper developed a series of original biocompatible fluorescent dyes(ECZ and ECX)with maximal absorption at 800 nm and 880 nm respectively.The merits of these dyes include high chemical stability,high photo-stability,high fluorescence quantum yield and convenience of further structural modifications.ECZ and ECX now make the spectral regioin of 800 to 950 nm available for bioimaging applizations.At the same time,these dyes also have great potentials in material based applications.A series of two-photon dyes with larger two-photon cross sections than Prodan were obtained during the development of long wavelength dyes and their emission wavelengths reaching 600 nm.Xanthene dyes are often used for biosensing,angiography etc.The stabilities of existing xanthene dyes still need further improvement.In this paper,we designed a new synthetic route and successfully introduced bulky steric groups onto the C-12 and C-15 of the xanthene dyes.The sterically protected dyes have better chemical stability than those non-protected.At the same time,the large steric groups also effectively prevent the dye from aggregation.Fluorescent probes are used widely in medical diagnosis and fluorescence guided surgery etc.In this paper,we designed a sensor with the principle of "covalent assembly",in which the substrate triggered the cascade reaction and then the fluorescent dye generated in situ with enhanced fluorescence signal from zero background.The merits of the sensor include simple structure,rapid detection and high selectivity.In addition,the "covalent assembly" strategy can be used in construction of sensors for many other substrates.A series of two-dimensional orthogonal dyes were synthesized.The core structure of the dye is characterized by the fact that the two dyes are connected together by vertical rigidity of a spiro type likage.These spiro-dyes could change the polarization plane of the incident light with 90° and can be potentially used in materials and biological research.In conclusion,this paper successfully developed multi-series high-performance dyes which meet the needs of biomedicine research.