Design And Evaluation Of SiRNA Liposomes Constructed By Poly(2-Ethyl-2-Oxazoline)-Cholesteryl Methyl Carbonate

In this paper,DOPE and DC-Chol were used as membrane materials to prepare cationic liposomes(CLs),further prepared CL/siRNA,the PEOZ-CHMC that a new type of polymer material was modified on the surface of CLs,and delivering siRNA to the target site.The fluorescence analysis determination method was established for siRNA.This method could provide the basis for the preparation and characterization of siRNA liposomes.CLs were prepared by thin lipid film method,CL/siRNA was prepared by mixing siRNA and CLs at weight ratio of 5:1(DC-Chol:siRNA,w/w),PEG-L/siRNA and PEtOz-L/siRNA were prepared respectively.The morphology,particle size,Zeta potential and encapsulation efficiency were investigated to evaluate the three kinds of CL/siRNA.Compared with CL/siRNA,the addition of PEtOz and PEG made no effect on particle size and the absolute value of Zeta potential decreased,and had no influence on encapsulation efficiency.Diluted the different types of CL/siRNA,and investigated the dilution stability.The results showed that the stability of CL/siRNA,PEG-L/siRNA and PEtOz-L/siRNA is all good.And the serum stability results also showed that compared to the CL/siRNA,PEG-L/siRNA and PEtOz-L/siRNA exhibited good stability in serum,it illustrated that PEtOz endowed CLs with good stability.Hemolysis assay results showed that PEtOz-L/siRNA did not occur hemolytic phenomena.And the cell viability proved that with the increase of the phospholipid concentration,the cytotoxicity of CLs increased.And in the experiment concentration,PEG-L/siRNA and PEtOz-L/siRNA reduced the slight cytotoxicity of CLs.Indicating that PEtOz-L/siRNA was safe and non-toxic.The cells experiment in vitro showed that the transfection and cellular uptake rate of PEG-L/siRNA and CL/siRNA had no difference under different pH conditions.But under the same pH condition,the transfection and cellular uptake rate of PEG-L/siRNA is lower than CL/siRNA,indicating that PEG blocked the cellular uptake of CLs partly.For the PEtOz-L/siRNA,at pH 6.4,the cell effect was superior to pH 7.4 obviously.These showed that PEtOz could endue pH sensitivity to CL/siRNA.Especially at the pH 7.4 and 6.4,the transfection and cellular uptake were higher than PEG-L/siRNA and CL/siRNA.Indicated that PEtOz did not affect the cellular uptake of CLs,which could overcome the dilemma of PEG.And all above results were confirmed that the non viral vectors of PEtOz modified CLs had potentiality to delivery the gene medicine of siRNA.