Preparation And Application Of DNA Based Nanoscale Targeting Drug Carrier

Deoxyribonucleic acid（DNA）is a biological macromolecular that carries the genetic instructions of all known living organisms.Since the discovery of the double-helical structure of DNA in the 1950^th,DNA gradually has become a popular material studied in field of drug delivery due to its programmable property,high stability and its memory of chain direction.In this study,a novel DNA nanoparticle,containing drug-loading domain,DNA aptamer and p H-sensitive spacer,was designed and synthesized.The DNA nanoparticles were applied to load anti-cancer drug and targeted tumor cells uptake.This thesis includes three main parts.In the first part,a novel single strand DNA template which integrated drug-loading domain,DNA aptamer and pH-sensitive spacer was designed.The feasibility of the design was validated by electron microscopic analysis.In the second part,using the designed template as the starting material,through hybridization,ligation and rolling circle amplification,the DNA nanoparticles with drug loading capacity,targeting ability and pH responsive drug-releasing ability were prepared.The assembling process was analyzed by Turbiscan Lab.The DNA nanoparticles were analyzed by microscopy（e.g.,light microscopy,electron microscopy,atomic force microscopy）,by particuology（nanoparticle tracking analysis）and by pharmacy（stability analysis and mechanism of drug loading analysis）.In the third part,drug-loading experiment was performed with the prepared DNA nanoparticles.By evaluating the drug-loading capacity of the DNA nanoparticles,the feed ratio of DNA to drug was determined.In in vitro drug release experiment,at pH5.4 the cumulative release of doxorubicin within 204 min was 4.26-fold of that at pH7.4,which suggested that the doxorubicin release process was triggered by the acidic pH of the environment.Furthermore,by the cell uptake experiment performed with targeted tumor cells and untargeted tumor cells,on cell level,the targeting ability of the DNA nanoparticles was validated.All the contents above have never been reported at present.