Targeted Polymer Nanoparticles Assist In The Integrated Treatment Of Clinical Tumors

At present,the process of integrated clinical tumor treatment is to first remove solid tumors by surgery,and then to kill residual or metastatic tumor cells by chemotherapy,radiotherapy,gene therapy,etc.,to prevent recurrence.These treatments may affect healthy tissues or organs,causing a series of side effects.For example,cancer recurrence caused by a positive margin in tumor surgery;chemotherapy and radiotherapy affect other healthy tissues and organs,and hinder the progress of cancer treatment.Therefore,there is an urgent need to develop efficient,safe and feasible means to achieve precise tumor resection and targeted tumor therapy.Nanomedicine is a research field that combines nanoscience,nanoengineering,and interaction between nanotechnology and life sciences,and has become an important development direction of modern medicine.Among them,nanotechnology refers to the scientific field that focuses on the synthesis,characterization,and application of materials and functional systems with nanometer particle size.Nowadays,people's interest in these materials is not only due to their small size,but also their unique physical(electrical,optical,magnetic)and chemical properties in the nanometer dimension(compared to the same material on the macro scale),while It can expand the interaction between cells and biomolecules.In addition,because it is easy to synthesize and functionalize different parts,low immunogenicity and toxicity,the application of nanotechnology in the medical field has promoted the development of diagnostic,therapeutic,and assisted surgical imaging methods,especially in the application of such as cancer.In this project,a bioresponsive carrier with supramolecular assembly charge shielding structure was designed for gene therapy and photothermal imaging system based on functionalized polydopamine to achieve precise tumor resection.The main research work of this thesis as follows:1.Nano spray based on functionalized polydopamine for thermal imaging assisted precise surgical resection of tumorGene therapy and drug therapy have developed rapidly in the field of tumor therapy.However,surgical resection is still the main treatment method for most solid sarcomas.Positive margins(indicating an increased likelihood of residual disease in the tumor bed)remain a huge challenge.In this study,polydopamine microsphere spray based on RGD modified surface was developed for thermal imaging assisted tumor precise resection.A polydopamine microsphere(PDA-RGD)with a surface-modified RGD peptide and high light-to-heat conversion efficiency was prepared.The RGD peptide can specifically bind to???3 integrin that is highly expressed by tumors.Large-scale spraying of the material suspension to the suspected tumor area,after specific recognition and cleaning,PDA-RGD stays on the surface of the tumor site.The 808 nm near-infrared laser illuminated a wide range of coverage through a collimator.The tumor area containing PDA-RGD captured the thermal imaging image in the field of view with an infrared thermal imager to accurately determine the tumor edge area to assist in the precise removal of surgery.The successful preparation of PDA-RGD was proved by DLS,infrared spectroscopy,ultraviolet spectrophotometer,scanning electron microscope and transmission electron microscope.The optimal power of the PDA-RGD photothermal imaging system was 3 W/cm~2and the optimal irradiation time was 6 min.Its photothermal conversion efficiency was 54.27%.In the study of the selective experiment of PDA-RGD on tumor cells and normal cells,it was proved that PDA-RGD has a significant specificity for tumor cells highly expressing???3 integrin,and further confirmed by endocytosis experiments.Finally,experiments in tumor-bearing mouse animal models proved that it can accurately locate the tumor edge.The results show that the combination of nano spray and thermal imaging technology can visualize the entire tumor range from a macro perspective,and can accurately determine the tumor marginal area to assist in the precise removal of the tumor.2.Synthesis of bio-responsive carrier with supramolecular assembly charge shielding structure and their application in gene editing researchCRISPR/Cas9(clustered regularly interspaced short palindromic repeat/clustered regularly interspaced short palindromic repeat associated proteins 9)gene editing platform is a promising therapeutic tool for genetic disorders,due to its ability to manipulate the pathogenic gene in genomic level and to easily target specific gene by manipulating single-guide RNA.Overcoming a series of biological obstacles faced by gene carriers in the cascade delivery process remains a huge challenge.A CRISP/Cas9 delivery system carrier with a charge shielding shell and a cationic polymer core with glutathione degradation in response to synthesis was designed and synthesized.The shell(CD-HPG-FA)was HPG initiated by?-cyclodextrin(?-CD)as a nucleus,and tumor-targeted folic acid(FA)was modified on the HPG.The core(HPAA-BM)of hyperbranched polyamide-amine(HPAA)was grafted with benzimidazole(BM).The host-guest interaction of?-cyclodextrin and benzimidazole was used to assemble CD-HPG-FA into the outer layer of hyperbranched polyamide-amine to form a charge shielding shell.The carrier has good blood compatibility and anti-non-specific adsorption ability in blood circulation delivery due to the outer layer of HPG shielding shell protection to achieve long circulation.The carrier shell was specifically recognized by folic acid and the folate receptor of tumor cells,and after reaching the tumor target site,the shielding shell was removed under acidic conditions to restore the gene transfection effect.After entering the tumor cells,the cationic carrier was degraded by glutathione to release the CRISP/Cas9 gene editing system for therapeutic purposes.The physical and chemical properties were characterized by means of ~1H NMR,ultraviolet spectrophotometer,etc.,which proved the successful preparation of the core and the shell;the 2D-NMR spectrum proved that the core and the shell were self-assembled.The pH-responsive disassembly of?-cyclodextrin and benzimidazole and the glutathione-responsive degradation of HPAA were confirmed by gel permeation chromatography and fluorescence spectroscopy.Through agarose gel electrophoresis experiment and gene transfection experiment,the optimal mass assembly ratio of core/plasmid/shell was 10:1:100.The analysis results of DLS and TEM showed that the size shrinks before and after self-assembly,and the phenomenon of dimensional rebound after disassembly.Apoptosis experiments and cell cycle experiments showed that at pH 6.5 compared to pH 7.4,the gene editing system had a better effect on tumor cell growth inhibition.The in vitro tissues imaged by live imaging proved that the carrier had a significant enrichment in the tumor.The blood compatibility evaluation of the carrier proved that the carrier had good blood compatibility.The results showed that the design of the vector can overcome various physiological obstacles and deliver the payload to the tumor tissue with the best efficiency.In a broader sense,the vector can also be adapted to provide other types of gene delivery systems.