Preparation And Properties Research Of The Second Near-infrared Region Fluorescent Liposome

The second near-infrared region(NIR-?)fluorescence imaging has a high imaging resolution and tissue penetration and develops rapidly in recent years.IR1061 is a hydrophobic organic small molecule NIR-? fluorescent probe that can be rapidly metabolized in vivo and has good clinical transformation potential.In this paper,the liposome with high biocompatibility was studied to integrate diagnosis and treatment,and the enhancement of NIR-? fluorescence was further explored for in vivo angiography.The main contents include:(1)Doxorubicin-loaded NIR-? imaging cationic liposome(DOX-IR1061 CLP)was prepared for co-loading of contrast agents and therapeutic agents.Laser confocal experiments showed that it promoted the uptake of DOX by cells.In vitro cytotoxicity experiments showed that DOX-IR1061 CLP exhibited higher cancer cell inhibition rate than DOX(***P<0.001).(2)ICG-IR1061 fluorescence-enhanced liposome(DOX-IR1061 LP)was prepared.ICG and IR1061 synergistically enhanced NIR-? fluorescence,and obtained 3 times higher fluorescence intensity than IR1061 liposome(IR1061 LP).The mechanism of fluorescence enhancement was studied.According to the experimental results,fluorescence enhancement may be achieved by fluorescence resonance energy transfer between ICG and IR1061.In addition,it was found that octadecylamine-modified ICG-IR1061 cationic liposome(ICG-IR1061 CLP)further enhanced the fluorescence intensity of NIR-?,and obtained a fluorescence intensity10 times higher than that of IR1061 LP.The mechanism of fluorescence enhancement was studied.According to the experimental results,it is suggested that fluorescence enhancement may be achieved by fluorescence reabsorption.It was used for vascular imaging in mice to obtain an imaging resolution higher than that of the near-infrared region.(3)On the basis of preparation of ICG-IR1061 CLP,doxorubicin hydrochloride was added to combine the photothermal action of ICG with the chemotherapy of doxorubicin,and the prepared doxorubicin-DOX-IR1061 LP(DOX-ICG-IR1061 CLP)has enhanced breast cancer cell inhibition ability.In summary,the synergy between ICG and IR1061 is of great significance for NIR-? imaging research,and can provide reference for the research and preparation of highly biocompatible NIR-? probes.It was found that octadecylamine not only synergized with DOX to increase its anti-breast cancer ability,but also played a role in liposome fluorescence enhancement,further enhancing the NIR-? fluorescence intensity.