An efficient vector for gene delivery: alpha,beta-poly (3-dimethylaminopropyl-D,L-aspartamide).

PSI, as the potential peptide-like intermediate, is subject to simple chemical modification in order to obtain good non-viral carriers for gene delivery. This paper describes the facile synthesis and preliminary evaluation of alpha,beta-poly (3-dimethylaminopropyl-D,L-aspartamide) (PDAI) as a vector. Reaction of PSI with 3-dimethylamino-1-propylamine afforded PDAI in N,N-dimethylformamide (DMF) solution. Such biophysical properties of PDAI/DNA complexes as the particle size and the zeta potential were determined by dynamic light scattering assay. The complexes prepared at weight ratios ranging from 2 to 3 have an average size of around 200 nm and a zeta potential of around 10.0 mV. Gel electrophoresis assays confirmed that PDAI could compact DNA to form the complexes and protect DNA from enzymatic degradation by DNase I at the weight ratio above 2.0. Furthermore, PDAI was found to transfect HepG2 cells at a much higher efficiency than commercially available polyethylenimine (PEI) (W(w)=75,000 Da). MTT cytotoxicity assay demonstrated that PDAI also showed much less toxicity than did PEI, suggesting that PDAI is a new class of transfection reagent to be used as a safe vector.