Biodegradable starch derivatives with tunable charge density-synthesis, characterization, and transfection efficiency.

Regioselective oxidation of water-soluble starch and conversion with alkyl diamines resulted in defined cationic starch derivatives. Those were assessed in their potential for polyplex formation, biocompatibility, and transfection efficacy. The new polymers have the advantage of being biodegradable, being not cytotoxic at rather high concentrations (LC50 > 400 μg/ml) for C2 substitution, and reach transfection efficiencies comparable to commercial transfection reagents. The polymer with the highest transfection efficacy is a C12 substituted polymer (degree of substitution = 30 %) at N/P 3. The LC50 value of that highly modified polymer is still one order of magnitude lower than that of PEI 25 kDa.