Preparation Of PAMAM-HA Targeted Gene Drug Delivery Systems And Its Biological Properties Investigation

Therapy imports and expresses target gene to correct genetic defect or play a role in the cell by means of certain control method. Gene therapy is key to choose the appropriate carrier that transported the target gene to the target cells accurately and controlled it to effective expression aned give play to the role of treatment. Virus carrier had high transfection efficiency.But the virus carrier had more serious security problems. Non viral vectors include cationic polymers, cationic peptides and cationic liposome, etc. It had the advantages of targeting property, low cytotoxicity,high safty, and easy for structural modification and has become the hot point in gene therapy. PAMAM has internal cavity structure.The end groups can be precisely controlled and amino was easy to be protonation and have positively charged.PAMAM was easy to combine with DNA and form nano compound.So it can protect DNA and achieve the goal of transfection. As drug carrier and gene carrier has the advantage oflhigh stability and good biological compatibility, non-immunogenicity, low cytotoxicity.By reducing the positive charge on the surface with PAMAM surface modified,PAMAM as gene vector can improve gene transfection efficency and decrease cytotoxicity. Hyaluronic as natural water-soluble polymer has various good qualities that was appropriate as the drug carrier.HA had the advavantage of good biological compatibility, non immunogenicity,high biological activity and vulnerable natural degradation in the body by enzyme action, targeting. HA has good tumor targeting property and increases water soluble of complex, biological compatibility. PAMAM has good theoretical basis of carrying genes into cells.The present paper mainly completed preparation of PAMAM-HA/p EGFP gene expression system and further studied its physical and chemical properties, biological properties, the influence of targeting, etc; By the molecular weight of PAMAM, the grafting ratio and grafting density of HA, polycation/gene weight ratio(w/w), etc, gene expression system can be optimized.includingthat gene transfection efficiency can be improved and cytotoxicity can be reduced, carrier targeting property, and stability can be increase, etc.We had been synthesized various polymers PAMAM-HA containing different the grafting density(5%, 15%, 25%) and quantity of the graft(HA3850, HA17200) of HA. Polymer PAMAM–HA formed different weight ratio of each polymers with DNA, measured the determination of particle size and Zeta potential of each polyplexs and performed gel retardation assay;The cytotoxicity of each polymers was determined by MTT colorimetric assay in different cells. In fluorescence microscope transfection efficiency of each polyplexs was measured in different cells and transfection efficiency was quantitatively measured by Cells flow meter. The determination of particle size and Zeta potential of each polyplexs related to the molecular weight of PAMAM, the grafting density and quantity of the graft of HA, the weight ratio of each polymers; The cytotoxicity of each polymers related to the concentration of the polymer,the molecular weight of PAMAM and incubating time;Polymer 4G-HA3850-5% and 5G-HA3850-5% can form polyplex with DNA and transfect the cells in vitro. Cells transfection efficiency was close to that of polyplexs 4G PAMAM/DNA. PAMAM modified by the grafting density and quantity of the graft of HA can reduced the cytotoxicity; The gene transport capacity and transfection efficiency in vitro of polymer 4G-HA3850-5% and 5G-HA3850-5% was close to polymers 4G PAMAM and 5G PAMAM.