Liposome-loaded Indocyanine Green And Imiquimod For The Photothermal And Immune Synergistic Treatment Of Colorectal Cancer

Colorectal cancer is one of the most malignant cancers in the world that seriously threatens human life and health.However,traditional treatment methods are difficult to effectively treat patients with advanced colorectal cancer.In recent years,with the discovery of immune checkpoints,immunotherapy based on immune checkpoint inhibitors and immune factors is a very promising treatment.At the same time,photothermal therapy is also an effective treatment for colorectal cancer due to its safe,efficient and non-invasive removal of primary tumors.At present,various types of immune molecules and photosensitizers have been used as treatment attempts for tumors,but they all have the disadvantage of low availability in vivo.The emergence of various carrier materials can effectively improve these shortcomings.Liposome carrier materials have been widely studied and applied due to their advantages of good biocompatibility and functional modification.This thesis constructed and designed a photothermal and immune synergistic therapeutic preparation R837/ICG@Lip by loading indocyanine green(ICG)and imiquimod(R837)into lipsomes for the treatment of colorectal cancer.Under the irradiation of 808 nm laser,The preparation’s photothermal ablation effect on tumor tissues will produce tumor-associated antigens that cooperate with R837 to stimulate the body’s immune response,and further combine indoleamine 2,3-dioxygenase(IDO)inhibitors to produce a synergistic therapeutic effect on tumors.TEM images and DLS results show that R837/ICG@Lip is a vesicle-like spherical particle with a diameter of 158.7±12.6 nm;The results of in vitro experiments show that R837/ICG@Lip has a good photothermal conversion effect and can produce significant photothermal toxicity to CT26 cells;The results of in vivo experiments show that R837/ICG@Lip combined with IDO inhibitors can effectively inhibit CT26 subcutaneous tumors,and show a significant synergistic anti-tumor effect.Therefore,the R837/ICG@Lip preparation has the therapeutic advantages of high efficiency,non-invasiveness,high bioavailability and synergistic gain,and shows great application potential in the treatment of colorectal cancer.