一种芘类染料分子的制备及性质研究

Preparation and property studies of a new dye based on pyrene

本文设计合成了一种新型的四芘(Quadri(pyrene), QP)染料分子,通过核磁氢谱和质谱对其结构进行了鉴定,通过紫外吸收光谱和荧光光谱研究其光学性质.采用乳液法,在水相中将QP制成纳米粒子.同时,引入尼罗红小分子,并利用荧光共振能量转移原理,使纳米粒子发出630~670 nm的近红外光.

In recent years,molecules with aggregation-induced emission(AIE)effect have been applied rapidly in bioimaging.In this study,we utilize Resonance Energy Transfer(FRET)strategy to achieve NIR emissive nanoprobes.Firstly,a new dye(quadri(pyrene),QP)with AIE characteristic was designed and synthesized.The molecular structure was determined by mass spectrometry and nuclear magnetic resonance spectroscopy.Then,the optical properties were studied by ultraviolet-visible absorption spectroscopy and fluorescence spectroscopy.We found that the fluorescence intensity of QP nanoaggregates was much higher than that of QP monomer,exhibiting AIE feature.Meanwhile,the emission peak of QP nanoaggregates was at 510 nm in ethanol(nonaqueous phase).Then,using emulsion method,a CHCl3 solution containing QP monomer and poly(lactic-coglycolic acid(PLGA))was dropped into a water solution with polyvinyl alcohol(PVA)as the emulsifier,which was followed by sonication for 3 min.Subsequently,the CHCl3 was evaporated under stirring overnight in a fume hood.After centrifugation and washing for three times,QP-PLGA nanoparticles were prepared in water.The emission peak of QP-PLGA nanoparticles was still at 510 nm.In order to regulate the emission wavelength of QP-PLGA nanoparticles to near-infrared region,the FRET strategy was utilized.QP monomer,Nile Red(NR)monomer with near-infrared emission and PLGA were dissolved in CHCl3.Similar to the preparation of QP-PLGA nanoparticles,the QPNR-PLGA nanoparticles were obtained in water.The large overlap between UV absorption spectrum of NR and the emission spectrum of QP enabled NR as an acceptor of FRET in the QPNR-PLGA nanoparticles.By changing different molar ratios of QP and NR,we obtained different fluorescence emission spectra and excitation spectra,which showed that QPNR-PLGA FRET nanoparticles were constructed successfully.Moreover,with the increasing of NR,the color of QPNR-PLGA nanoparticles changing from green to red could be observed apparently by the naked eye under the 365 nm illumination in a UV lamp box.Eventually,the QPNR-PLGA nanoparticles could emit fluorescence in the range of 630 to 670 nm based on FRET,achieving the regulation of the fluorescence to near-infrared region.It is easy and effective for dyes with poor solubility and short-wavelength emission to emit nearinfrared fluorescence in water by utilizing emulsion method to prepare water-soluble nanoparticles and FRET mechanism to modulate the wavelength.The resultant near-infrared emissive nanoparticles are promising nanoprobes in bioimaging.