Characterization Of Chiral Polypeptide As Potential Immunoadjuvants

Polypeptide have been widely used in tissue engineering and drug delivery due to their good biocompatibility and biodegradability.In the recent years,polypeptide materials which have been used as potential immune adjuvants can establish an inflammatory microenvironment to promote immune response.However,the inflammatory microenvironment established by the existing immune adjuvants can not be controlled and achieve the desired immune response.To solve the above problem,we designed different chiral peptides-based hydrogels and nanoparticles in this work and verified the different inflammatory response caused by materials,details as follows:?1?Four kinds of chiral polyalanine block copolymers were synthesized by ring-opening polymerization?ROP?of NCA,The structures of the copolymers were analyzed by proton nuclear magnetic resonance?¹H NMR?,Fourier-transform infrared?FT-IR?and gel permeation chromatography?GPC?;the phase transitions of block copolymers in phosphate buffer solution?PBS?were observed by tube inversion method;the mechanical properties and surface morphology of hydrogels were observed by dynamic mechanical analysis and scanning electron microscopy?SEM?;the gel-forming mechanism was investigated by variable-temperature circular dichroism?CD?,variable-temperature dynamic light scattering?DLS?,and variable-temperature ¹³C NMR;hematoxylin and eosin?H&E?staining,immunohistochemistry as well as semi-quantitative analysis were used to investigate the degree of inflammation caused by hydrogels.The results showed that D-hydrogel could induce more obvious inflammatory reaction,and the inflammatory reaction could be controlled by regulating the content of D-amino acid to obtain immune responses.?2?Two kinds of chiral polyphenylalanine and polylysine block copolymers were synthesized by ring-opening polymerization of NCA,the structures of block copolymers were analyzed by ¹H NMR and FT-IR;the block copolymers were prepared into nanoparticles by nano-precipitation method,and then the particle size and morphology were analyzed by DLS and transmission electron microscope?TEM?;flow cytometry?FCM?and enzyme linked immunosorbent assay?ELISA?were used to analyze the endocytosis of copolymers and the content of interleukin-6?IL-6?induced by copolymers.The results also showed that D-nanoparticles could accelerate endocytosis and stimulate cells to produce more IL-6.Therefore,the desired immune effect can be achieved by regulating the content of D-amino acids.Different chiral polypeptide materials were designed to induce different degrees of immune response.This strategy has a good prospect in immunotherapy.