Fabrication,Characterization And Biological Application Of Near Infrared Nanoparticles

The design and construction of NIR fluorescent probes with near-infrared fluorescence emission,large Stokes shift,high fluorescence quantum efficiency,good light stability,low cytotoxicity and high biocompatibility is very important for deep research of life information and the guiding diagnosis and treatmernt of tumor.In this paper,AIE active fluorescent probes with Donor-Acceptor structure were constructed by using rhodanine as electron acceptor and triphenylvinyl aromatic compound as electron donor.By introducing electron-rich groups of furan and thiophene,the emission wavelength is red-shifted.Then,fluorescent probes were prepared into near infrared nanoparticles by using polyoxyethylene polyoxypropylene ether block copolymer(Pluronic F127)as encapsulating agent to enhance their biocompatibility.These AIE nanoparticles were applied to cell imaging,long-term cell tracing,long-term tracking of tumor growth and photodynamic therapy.(1)Firstly,the AIE fluorescent probe TPE-Rho with rhodanine as electron acceptor and tetraphenylethylene as electron donor was designed and synthesized.Amphiphilic polymer Pluronic F127 was used to fabricate TPE-Rho dots with uniform particle sizes distribution.Results show that TPE-Rho dots have strong stability,good biocompatibility,large Stokes shift(?200 nm),good permeability of cell membrane,and can be applied to live cell imaging and selective stain of cytoplasm.(2)A near infrared fluorescence probe TPFE-Rho with AEE activity was synthesized by introducing electron-rich group furan into TPE-Rho,using rhodanine as electron acceptor and triphenylvinyl furan as electron donor.The nanoparticles TPFE-Rho dots with uniform particle sizes distribution were fabricated by F127 as the encapsulating agent,TPFE-Rho dots can avoid the interference of background fluorescence,penetrate thicker tissues,avoid the interference of absorption wavelength and emission wavelength,and improve the signal-to-noise ratio of biological imaging as a result of their AIE activity,near infrared emission(654 um)and large Stokes shifts(?183 nm),excellent photostability and good biocompatibility.In vitro experiments show that TPFE-Rho dots labeled SK-Hep-1 cells still emitted red fluorescence after 11 passages.In vivo imaging data showed that TPFE-Rho dots could monitor the growth of tumors in real time for more than 19 days.(3)We further introduced thiophene group with stronger electron-donating effect to modify the structure of TPFE-Rho,and synthesized TPVTR,a fluorescent molecule with rhodanine as electron acceptor and triphenylvinylthiophene as electron donor.Then,it was coated with F127 and fabricated into organic fluorescent nanoparticles(TPVTR dots).TPVTR dots have near infrared emission(695 nm),large Stokes shift(210 nm),high luminescence intensity,grate photostability,excellent biocompatibility,good ability to generate reactive oxygen species and eminent phototoxicity.TPVTR dots labeled tumor cells still showed red fluorescence signal after 16 days,and tracked the growth of tumors in vivo for more than 8 days.TPVTR dots markedly reduced the survival rate of HepG2 cells,effectively inhibited the growth of tumors,and had good photodynamic therapeutic effect in illumination.These results indicate that TPVTR dots can be used as effective long-term tracer fluorescent probes and near infrared photosensitizers,and have broad application prospects in image-guided therapy.