Targeted delivery system of siRNA

Targeted delivery of small interference RNA(siRNA) is the key part for clinical therapy of siRNA agents.The ligand,antibody and aptamer have been used to design some delivery system which can effectively deliver siRNA to special tissue and cells.There are three steps for preparing the delivery system.Firstly,liposome or polymer spontaneously combines siRNA to form nanoparticle.Secondly,bridge molecules such as polyethylene glycol(PEG) are used to pack the nanoparticle.Thirdly,the ligand,antibody or aptamer are linked to PEG.