Research On Fluorescent Nanoparticles Based On Delayed Fluorescent Dyes

Thermally activated delayed fluorescence(TADF)light-emitting materials is developing rapidly in recent years,based on pure organic TADF molecules,transfer in organic electroluminescent,luminous,biomedical imaging and photodynamic therapy,and other fields have shown good application prospects.In the past few decades,nanotechnology has been effectively integrated with many traditional disciplines,and it has revolutionized many fields of science and technology.It is a subject of scientific research value to integrate nanotechnology with TADF organic dye molecules.In the early stage of our research group,many TADF molecules based on fluorescein derived dyes have been published,mainly focusing on the photophysical properties and bioimaging applications of these dye molecules at the small molecular level.In this paper,two fluorescent nanoparticles,NP-1 and NP-2,have been synthesized by the preparation of a TADF molecular DPK-DCF and the preparation technology of inorganic silicon nanoparticles.NP-1 is the outer surface of the DPK-DCF molecules connected to the silica nanoparticles,while NP-2 is the internal of the DPK-DCF coated with silica nanoparticles.Through the study on the physical properties of their light,found that fluorescent nanoparticles NP-2 under the condition of the PBS solution pH = 7.4,the luminescence lifetime is 9.47 ms(deoxygenating condition)and 9.33 ms(air atmosphere condition)at a wavelength of 574 nm respectively;fluorescent nanoparticles NP-2 has a luminescence lifetime of 15.93 ms at 575 nm in solid state.The results showed that the fluorescent nanoparticles constructed by TADF dye molecules showed a long life span of nearly three orders of magnitude higher than that of pure organic dye molecules.This paper further studies the fluorescent nanoparticles NP-1 and NP-2 performance of photodynamic therapy,found that fluorescent nanoparticles NP-1 and NP-2 even using near infrared 660 nm leds for illumination,in solution can effectively generate singlet oxygen.The photodynamic therapy of tumor cell Hela in vitro was tested with fluorescent nanoparticles NP-1.