Design,Preparation And Properties Research Of Poly (Amino Acid) Gene Vectors

Polyamino acid is a kind of degradable polymer material which has natural protein-like structure and good biocompatibility.It has broad application prospects in biomedical fields such as drug delivery and gene delivery.The side-group functional modification of polyamino acids plays an important role in regulating the performance of polyamino acid materials.Polylysine is one of the typical representatives.However,polylysine with only primary amino groups has some drawbacks: low molecular weight with low transfection efficiency;high molecular weight with high cytotoxicity;and poor membrane activity,which is detrimental to internalization.Therefore,how to balance cytotoxicity and transfection efficiency is the key to improving polylysine.Polylysine-polyleucine amphiphilic block copolymers were prepared by NCA ring-opening polymerization.However,compared with Polyethyleneimine(PEI-25K),this amphiphilic polymer does not exhibit significant advantages.Therefore,we introduce guanidine-containing arginine or amino-containing lysine into the polylysine side chain by EDC condensation.The modified polylysine-polyleucine amphiphilic block copolymer is a side-chain functionalized polyamino acid gene carrier that can be complexed with DNA to form nanoparticles with better cell internalization ability.The structure of the product was characterized by means of nuclear magnetic resonance spectroscopy,infrared spectroscopy and gel permeation chromatography.Ensure the functionalized polylysine-based polymer was successfully synthesized.The cytotoxicity of the material was characterized by MTT method.The results showed that the cytotoxicity of the material was low,and the transfection experiment was used to verify the material's reliable transfection performance.It is an excellent gene carrier.In this work,the performance of the vectors is significantly improved by simple small molecule side group modification,which provides a new idea for the modification of cationic polymer carrier.