Research About Application Of Microfluidic System On Antigen Nano-carriers

The use of tumor antigens on cancer therapy vaccines is a new method of tumor immunotherapy,but the tumor antigen immunogenicity is weak,especially the poor ability to cause cell immunity.Antigen nanoparticles can promote the APCs uptaking and presenting antigens,thereby enhancing the immune response.In the early work of our laboratory,we used PEI with positive charges to combine with negatively charged model antigens to obtain antigen nanoparticles,which improved the cross-presenting of dendritic cells to antigens.However,the traditional preparation of such electrostatic complexes using vortexing method has poor controllability and repeatability and it is difficult to enlarge,limiting the application of PEI on tumor vaccines.The microfluidic method can achieve highly controllable operation.We hope that this method can improve the controllability and reproducibility of the preparation process,the homogeneity of PEI/OVA nanoparticles and the biological effect of the preparations.At first,we did a preliminary study of four kinds of chips based on different design principles.It showed that microfluidic operation had no effect on the structure and function of the protein under the flow rate we chose.Besides,we found although the four kinds of chips showed different mixing efficiency in numerical simulation,there was no significant difference in the formation effect of nanoparticles in some PEI/OVA mass ratio conditions.Finally,we chose the Tesla chip and PEI for the next study.We compared the microfluidic method with vortexing,studied the possible influence factors of PEI/OVA complexes preparation by Tesla chip,and compared size,zeta potential,the binding rate,cytotoxicity,antigen cross-presenting effect of PEI/OVA complexes with different mass ratios.In the study,we found that the PEI/OVA nanoparticles prepared by microfluidics were more homogeneous and reproducible than those prepared by vortexing.Microfluidics greatly expanded the preparation range of PEI/OVA complexes.We established a reliable method of microfluidic preparation.Based on the above research,in order to reduce the toxicity of PEI/OVA nanoparticles,with PEG modified PEI,we prepared PEG-PEI/OVA complexes by Tesla chip and studied their physicochemical properties and biological effect.The results showed that PEG-PEI/OVA complexes had reduced cytotoxicity.In addition,DCs had strong endocytosis on the complexes,and the complexes also had good antigen cross-presentation effect.In order to improve the antigen presentation effect of PEG-PEI/OVA complexes,we further added the immune adjuvant CpG into the binary complexes to form the ternary complexes and researched some contents like cross-presentation of DCs and co-stimulatory molecules expression.In summary,microfluidics is applied to the preparation of PEI-based antigen delivery system,so preparation method is optimized,the effect of formulations is improved and its application range is expanded.Microfluidics is beneficial for the commercialization and industrialization of PEI-based protein antigen delivery system.In addition,the role of PEG-PEI and immune adjuvants in antigen delivery vectors was investigated in this paper,which laid the foundation for the next study.