Design And Preparation Of Porous Nanoparticle And Microparticle Tumor Vaccines And Application

The purpose of tumor immunotherapy is to stimulate the body’s cellular and humoral immune response,and rely on its own immune mechanism to obtain effective treatment.Tumor vaccine is one of the research hotspots of tumor immunotherapy,it is an immunotherapy method that uses a carrier to load tumor-specific antigens and injects them into the body to exert therapeutic effects.Free antigens have a poor immune effect,are less phagocytosed by cells,and easy to be degraded.Tumor vaccines use carriers to carry tumor-specific antigens and are injected into the body to play a good role.The carrier can effectively protect the antigen from degradation,and because of the characteristics of the carrier itself,it can stimulate the immune response.In this thesis,sphereSiO₂（sSiO₂）,flower-likeSiO₂（fSiO₂）,and Ca CO₃microparticles（NM）,all three carriers can effectively improve the antigen phagocytosis of antigen-presenting cells,promote the maturation and activation of dendritic cells,and stimulate the occurrence of cellular immune response,which has played a certain effect in melanoma tumor models.In this thesis,the carriers were characterized by scanning electron microscopy（SEM）,transmission electron microscopy（TEM）,laser particle size analyzer（DLS）,Fourier Infrared Spectroscopy,surface zeta potential,and energy dispersion X-spectroscopy.The load of the antigen was measured by the BCA method.CCK8 was used to evaluate the toxicity of tumor vaccine,and the flow cytometry（FACS）of dendritic cells was used to analyze the engulfment of tumor vaccines,and the tumor vaccine activated dendritic cells.The confocal laser scanning microscope（CLSM）was used to observe the distribution of tumor vaccine in dendritic cells and the lysosomal escape of the antigen.Small animal imaging technology was used to observe the migration of tumor vaccine in real time.Finally,animal models were used to evaluate the therapeutic effect of tumor vaccines on melanoma:（1）sSiO₂have a particle size about 320 nm,with a good morphology and uniform particle size.sSiO₂had certain modification groups that can be modified to support the antigen.Load capacity up to 458 mg g^-1_support;the cytotoxicity results indicating that sSiO₂has good biocompatibility;compared with the free antigen group,the sSiO₂group can significantly promote the phagocytosis of antigens by cells,and can promote the maturation of BMDCs and cross-presentation.In vivo imaging results showed that sSiO₂can protect the antigen from rapid degradation and prolong the retention time of antigen in the body.H&E staining also supported the fact that biocompatibility was great.（2）The particle size of fSiO₂was about 328 nm,with obvious flower-like structure,BET surface area and porosity were 477.35 m²g^-1and 1.504 cm³g^-1,respectively.Amount of load up to 630mg g^-1_support.FACS and CLSM showed that fSiO₂can promote phagocytosis of antigen.fSiO₂can also improve the cross-presentation of antigens,promote the maturation and activation of BMDCs.Animal experiment results show that fSiO₂has excellent anti-tumor effects and can stimulate the body’s anti-tumor immune response.（3）NM was a micron carrier with a particle size about 5μm.Through EDS mapping,fSiO₂can be uniformly distributed in NM.Both FACS and CLSM showed that NM can promote phagocytosis of antigens.Especially in CLSM,OVA@NM can promote lysosomal escape to stimulate cellular immune response.OVA@NM promoted cross-presentation,had good biocompatibility,and can protect antigens from rapid degradation for a long time.Animal experiments show that NM can promote anti-tumor immune response.