Adding two C20 or C22 chains, both mono-cis-unsaturated, N4, N9-dieicosenoyl spermine and N4, N9-dierucoyl spermine, gave efficient siRNA delivery vectors, even in the presence of serum, comparable to TransIT-TKO and with excellent cell viability.

The aims of this work are to study the effect of varying the chain length in synthesized N4,N9-diacyl spermines on DNA condensation and then to compare their transfection efficiencies in cell lines. The five novel N4,N9-diacyl lipopolyamines: N4,N9-[didecanoyl, dilauroyl, dimyristoyl, dimyristoleoyl, and dipalmitoyl]-1,12-diamino-4,9-diazadodecane were synthesized from the naturally occurring polyamine spermine. The abilities of these novel compounds to condense DNA and to form nanoparticles were studied using ethidium bromide fluorescence quenching and nanoparticle characterization techniques. Transfection efficiency was studied in FEK4 primary skin cells and in an immortalized cancer cell line (HtTA), and compared with a saturated (distearoyl) analogue and also with the non-liposomal transfection formulation Lipogen, N4,N9-dioleoyl-1,12-diamino-4,9-diazadodecane. By incorporating two aliphatic chains and changing their length in a stepwise manner, we show efficient circular plasmid DNA (pEGFP) formulation and transfection of primary skin and cancer cell lines. Two C14 chains (both saturated or both cis-monounsaturated) were efficient transfecting agents, even in the presence of serum, but they were too toxic. N4,N9-Dioleoyl spermine efficiently condenses pDNA and achieves the highest transfection levels with the highest cell viability among the studied lipopolyamines in cultured cells even in the presence of serum.

N4,N9-Distearoyl spermine and N4,N9-dioleoyl spermine are efficient siRNA formulation and delivery vectors, even in the presence of serum, comparable to TransIT-TKO. However, four positive charges distributed as in spermine was significantly more toxic.

No abstract