Design And Application Of Organic Molecule NIR-Ⅱ Optical Diagnostic Reagents

In recent years,optical diagnosis and treatment technology has become an effective method for early detection and treatment of cancer due to its excellent clinical detection capability and therapeutic effect.Compared with the visible light window(400-700 nm)and the near-infrared-I window(700-900 nm)fluorescence imaging technology,the fluorescence imaging technology in the near-infrared-Ⅱ window(NIR-Ⅱ,1000-1700 nm)is because of its higher emission wavelength.These advantages can lead to higher spatiotemporal resolution,deeper tissue penetration depth,and improved overall image quality in NIR-Ⅱ fluorescence imaging.It has great applied research value in the field of biomedicine.Photothermal therapy is an effective and non-invasive method for the treatment of cancer,which mainly relies on the local heating effect of photothermal agents to convert light energy into heat energy to eliminate cancer cells.Today,various inorganic photothermal agents such as gold nanorods,carbon nanomaterials,metal sulfides,etc.,have been developed for photothermal therapy.However,inorganic photothermal agents usually have poor biodegradability and potential toxicity,which limit their clinical application.The chemical and optical properties of organic photothermal agents can be tuned by specialized synthesis,resulting in good biodegradability,low toxicity,good photothermal conversion efficiency,and high photostability.Because of these unique properties of organic photothermal agents,they have been ingeniously developed and designed for optical therapy.Based on these,the paper proposes two new ideas for phototherapy guided by near-infrared second-region fluorescence imaging.The specific research contents are as follows:(1)NIR-Ⅱ fluorescence imaging guides DPP organic small molecule-based photothermal therapy: Guided photothermal therapy of DPP organic small molecule-based nanoparticles by 808 nm laser excitation material NIR-Ⅱ fluorescence imaging.Such nanoparticles are easy to synthesize and have good stability.It has a good NIR-Ⅱ fluorescence signal and high photothermal conversion efficiency(41.5%)under laser irradiation,and has excellent photothermal stability.After the nanoparticle was co-cultured with NIH-3T3 normal cells,it was found that the normal cells basically had no obvious death phenomenon,but after co-culture with Hela cancer cells and then irradiated with 808 nm laser,it was found that it had a significant killing effect on cancer cells.The above experimental results confirmed that the nanoparticles have good biocompatibility,low toxicity to normal cells and good photothermal treatment effect.These studies provide a basis for tumor photothermal therapy guided by NIR-Ⅱ fluorescence imaging and provide strong support for future clinical applications.(2)Construction of high-performance photothermal agents and photothermal therapy guided by NIR-Ⅱ imaging: The NIR-Ⅱ fluorescence imaging nanoparticles were designed through molecular structure regulation,and the photothermal therapy triggered by 1064 nm laser was realized.In this chapter,we successfully designed and screened a novel multifunctional nanoparticle T1-NPs based on symmetric organic small molecules.The nanoparticles have strong light absorption at 1064 nm,excellent NIR-Ⅱ fluorescence emission performance,and high photothermal conversion efficiency(45.3%).In addition,in vitro cell experiments under 1064 nm laser irradiation,the nanoparticles showed excellent cancer cell killing effect(mortality over 90%).A single laser irradiation has a significant inhibitory effect on mouse tumor growth(tumor inhibition rate exceeds 90%).This work provides an innovative idea for constructing a nanoplatform for high photothermal therapy guided by near-infrared second-region fluorescence imaging.