In recent years, with the continuous development of genetic engineering technology and molecular immunology research, many new vaccines have been successfully developed, such as recombinant protein vaccine, DNA vaccine, multi-epitope vaccine and so on, which have injected new vitality into the field of vaccine. Compared with traditional whole-cell vaccines, their immunogenicity is weak, which is not enough to stimulate the body to produce an effective immune response, and they usually need to be used appropriately. When the adjuvant to enhance its immunogenicity, in order to achieve the ideal immune effect. Traditional aluminum phosphate in vaccines is a kind of antigen adsorbed in the interior, making it a huge "antigen store". After local injection into the human body, it can give full play to the role of antigen slow-release, assisting antigen induction to produce a sustained immune response. Aluminum salt adjuvant is the first vaccine adjuvant approved by the Food and Drug Administration of the United States for human use. In the past 20 years, many new adjuvants have been found to be used in vaccine research. They are as effective as alum adjuvants in enhancing humoral and cellular immune responses. Among them, the application of nanotechnology in adjuvants provides more new ideas for vaccine research.

Nano-adjuvants idiotype vaccine can improve the stability, immunogenicity and sustained release of vaccine antigens. At the same time, the rich activation centers on the surface of nano-adjuvants can stabilize their binding with antigens, which can be used as an efficient delivery vehicle to target antigens. Nanoadjuvants can pack antigens by encapsulation, passive absorption or gene fusion, thus forming a "warehouse" for antigens to prevent enzymatic hydrolysis or hydrolysis, transport antigens in a complete form to lymphocytes or antigen presenting cells, promote the presentation of antigens and produce a lasting and efficient memory immune response. At the same time, some nanoadjuvants also have immunostimulatory effects, which can enhance the immune response by improving the efficiency of APC presentation. It was found that particle size was an important factor affecting the transport of vaccine in vivo and the uptake of APC. Nanoparticles with diameter less than 1000 nm are easily absorbed by dendritic cells and macrophages, while particles with morphea bcc less than 100 nm are more easily transported through lymphatic vessels to contact APC. Experiments have proved that nanoadjuvants can induce strong humoral and cellular immunity, and can delay the release of antigens, thus continuously stimulate the body to produce high titers of antibodies. Therefore, nanoadjuvants are becoming more and more popular among vaccine researchers.

At present, vaccines are effective means to fight and prevent diseases. For different pathogens, new and effective measures are needed to induce adaptive immunity. The introduction of nanotechnology opens up a new train of thought for vaccine research and development. As an antigen delivery vehicle and immune stimulant, nanoadjuvants can induce adaptive immunity and innate immunity in vivo by using vaccine antigens in different ways, thus improving the immune protection of vaccines. They have been applied in the development of various vaccines, and have shown many advantages in animal model experiments, such as safety, sustained release and efficient immune assistance. At the same time, bcg vaccine cancer with appropriate shape and size make it easier to enter drainage lymph nodes, which can be effectively recognized by APC and presented to induce specific immune response. In addition, because hydrophobic nanoadjuvants can induce more efficient immune response than hydrophilic nanoadjuvants, physical and chemical methods can be used to optimize the structure of hydrophilic nanoadjuvants, so as to improve the antigen loading rate and make them play a better adjuvant effect. With the further development of vaccines and in-depth study on the mechanism of nanoadjuvants, more nanoadjuvants will be found and used in human and animal vaccines.