| Oligodeoxynucleotides (ODNs) have been shown to inhibit cellular and viral gene expression at the molecular level. This technology offers a potential therapy action in various diseases including tumors. However, several problems, such as metabolic stability, efficient cell internalization of ODNs and their efficient entrapment into liposomes still limit this approach appreciably. To improve target specificity and biological activity of ODNs, three different length of poly(L-lysine) (PLL) which were conjugated to ODN was studied, and these conjugates were encapsulated in N-SLBA liposomes, N-SLBA is a ligand for the asialoglycoprotein receptor. We investigated their effects on cell transfection and bioactivity.The following parts are included in this paper:1 Synthesis and identification of ODN, PLL-ODN and N-SLBA.ODN (5' cga tgg cac ggc gca ctt 3' ) targeted to survivin mRNA was synthesized, we introduced a simple phosphoramidite method to produce ODN. The purity of ODN reached to 98% purified by HPLC. At the same time, the antisense sequence is 5' cga tgg cac ggc gca ctt 3' identified by UV, IR and MS. The physicochemical property of ODN was studied, the results indicated that: pI of ODN is 2.26-2.34; n-octanol/water partition coefficient is 0.16; ODN was degraded in the sun and high temperature, we should store it avoiding sunlight at 4℃.ODNs was covalently linked to different length poly(L-lysine) (MW 1000, 2000 and 10000) via a N-morpholine (azahexopyranose) ring after periodate oxidation of their 3' - terminal ribose. However, it was necessary to add an oxidizable pCp, this operation were performed with T4 RNA ligase. The synthetic ODN was covalently...
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