Construction Of Near-infrared Nanodrug System And Research In Multi-Mode Tumor Therapy

Cancer is one of the main killers threatening human life and health in the world,so research on tumor treatment has been a key subject of scientific research.For chemotherapy and radiotherapy,which are widely used in clinical treatments of tumors,they have a large adverse effect while producing a therapeutic effect on tumors,and a single treatment method has limited inhibition of tumor growth and development.Therefore,it is necessary to build a new drug delivery system to achieve the purpose of accurate and safe drug delivery and to achieve the combination of multiple treatment methods.Nanoparticles have excellent performance in achieving multifunctional drug delivery,which is also a hot topic in recent years.In this paper,we have designed and synthesized two multifunctional drug delivery systems.For the multifunctional nanodrug delivery system PTX-R837-IR820@TSL,we verified the drug delivery and combination therapy effects of nanoparticles in vitro,at the living cell level,and in mice,respectively.We have verified the success of nanoparticle formation through multiple methods,as well as excellent responsive drug release capabilities for photothermal and photodynamic treatment capabilities with photosensitizers.Besides,cell-level evaluations show that nanoparticles are effective for killing.For in vivo experiments,we evaluate nanoparticles from both targeting and therapeutic aspects.For nanopolymer FA-PEG-PEI-UCNP-Ce6/siRNA,we only examined its structural characteristics and in vitro photodynamic ability.Experiments have shown that the two multifunctional drug delivery systems we constructed have good therapeutic potential.The main line of this thesis is to prepare two kinds of multifunctional drug delivery systems,and perform multi-level detection of tumor treatment with one of the nanoparticles,which provides a new idea for tumor drug delivery.This dissertation is divided into eight parts,as follows:Chapter One:IntroductionThis chapter mainly elaborates the theoretical and practical significance and research background,research status,research ideas,experimental design,technical methods and means adopted,and overall structural arrangement of the dissertation.Chapter Two:Literature ReviewThis chapter mainly introduces the research status of tumor treatment,summarizes the advantages and disadvantages of various treatment methods,and the direction of tumor treatment.A brief introduction to nanodrug delivery systems is given,and the development status of various nanodrug delivery systems is summarized,and the classification,characteristics,advantages and disadvantages of thermosensitive liposomes?TSL?are highlighted.Chapter Three:Construction and Characterization of Multifunctional Nanodrug Loading System PTX-R837-IR820@TSLIn this chapter,a multifunctional drug delivery nanoparticle is constructed in order to solve the poor water solubility,the toxic and side effects caused by non-targeted therapy,and the limitation of chemotherapy alone in the treatment of gastric cancer of the clinical gastric cancer treatment drug paclitaxel?PTX?.Nanoparticles use TSL as a carrier with high light-to-heat conversion efficiency IR820 as a photodynamic agent,a photothermal agent,and a fluorescent dye which is loaded on liposomes to construct photothermal sensitive liposomes.At the same time,the chemotherapeutic drug PTX and the immunoadjuvant toll-like receptor 7 agonist?R837?were uploaded to the photothermal sensitive liposomes,so that the liposomes have multiple ways,namely chemotherapy,photothermal therapy,photodynamic therapy and immunotherapy combination therapy.The experiments demonstrate the structure and function of liposomes by evaluating the particle size and near-infrared fluorescence of the liposome particles.In summary,the experiments in this chapter illustrate the successful synthesis of a multifunctional nano delivery system.Chapter Four:Study on Drug Release Kinetics of Multifunctional Nanodrug Loading System PTX-R837-IR820@TSLIn this chapter,the photosensitizer IR820 with light-to-heat conversion function is added to 1,2-palmitoylphosphatidyl glycerol?DPPG?liposomes.The photosensitizer in the interior is exposed to near infrared light?808nm?.The conversion of light energy into thermal energy interacts with the structure of the phospholipid membrane,and the structural conformation of the liposome phospholipid membrane changes,resulting in drug release.The experiment evaluates the heat-responsive drug release ability of the multifunctional drug-loading system by explaining the release of the photothermal sensitive liposome complex to the drug under different circumstances,which lays the foundation for future in vivo treatment of small animals.Chapter Five:Study on Photothermal Conversion Efficiency and Singlet Oxygen Production of Photosensitizer IR820The main purpose of the experiments in this chapter is to detect the light-to-heat conversion capacity and the singlet oxygen generation ability of IR820 as a new indocyanine green photosensitizer.The purpose of the experimentally constructed multifunctional drug delivery nano system is to combine chemotherapy,photothermal therapy,photodynamic therapy,and immunotherapy to treat tumors.Among them,the function of the new indocyanine green photosensitizer IR820 assumes two responsibilities of the multifunctional drug delivery nano system that can realize photodynamic therapy and photothermal therapy.Therefore,the excellent photothermal conversion efficiency and singlet oxygen generation ability of the photosensitizer IR820 is essential for the realization of the function of the multifunctional drug delivery nano system.The release of PTX under the irradiation of near-infrared light shows that the photosensitizer IR820 can convert light energy into thermal energy,and the converted thermal energy can make the thermosensitive liposome respond.At the same time,the test shows that IR820 can also generate singlet oxygen,which integrates photothermal therapy with photodynamic therapy.Chapter Six:Cell Evaluation of Multifunctional Nanodrug Loading System PTX-R837-IR820@TSLThe purpose of this chapter is to verify the therapeutic effect of PTX-R837-IR820@TSL nanoparticles in vitro,and to lay the foundation for subsequent animal experiments.We select the most common MTT experiment to evaluate the treatment effect of the PTX-R837-IR820@TSL nanoparticle in vitro.The killing effect of various treatment methods on tumor cells is evaluated through different treatment groups,and the effect of combined treatment is evaluated at the cell level.Chapter Seven:Multifunctional Nanodrug Loading System PTX-R837-IR820@TSL in Vivo DetectionThis chapter examines the efficacy of photothermial sensitive liposomes constructed in combination with photothermal therapy,photodynamic therapy,chemotherapy,and immunotherapy in tumor-bearing mice.The tumor-bearing mice were grouped for treatment,and the effect of each drug in the combination therapy and the effect on other treatment methods were evaluated.The experiment demonstrated the combined therapeutic effect of the multifunctional drug delivery system by evaluating the targeting of the multifunctional drug delivery system,the treatment of mice?tumor volume,mouse survival curve?,the maturation rate of dendritic cells?DC?,and immune inflammatory factors in mice.Chapter Eight:Synthesis and Characterization of Upconversion Nanopolymer FA-PEG-PEI-UCNP-Ce6/siRNAA multifunctional drug delivery nanopolymer is constructed in this chapter.Nanoparticles are mixed with NaYF₄:Yb,Er upconversion luminescent nanocrystals with high upconversion efficiency and Ce6 as the photosensitizer,and at the same time,the positively charged hydrophilic substance FA-PEG-PEI is coated on the hydrophobic nanomaterial as a carrier,and the negatively charged siRNA is adsorbed by electrostatic adsorption,so that the upconversion nanopolymer has the function of multiple therapeutic methods,that is,a combination of photodynamic therapy and immunotherapy.We have discussed the effect of different composition on the size and potential of the nanoparticles.The singlet oxygen production experiment verified that FA-PEG-PEI-UCNP-Ce6/siRNA can be excited under a 980nm laser and efficiently generate singlet oxygen.The 980nm laser excites upconversion luminescent nanocrystals and Ce6 is excited by the fluorescence emitted by the upconversion nanocrystals.In summary,this chapter intends to demonstrate the successful synthesis of a multifunctional nano delivery system.