polyethyleneimine

Polyethylenimines (PEI) are low to high molecular weight compounds with the general formula -[CH2-CH2-NH2]-, made by ring opening polymerization of aziridine. These polymers are available as linear, partly branched or repetitively branched polymers (dendrimers). The linear form contains only primary amines in the backbone whereas branched PEI also contains secondary and tertiary amines. Thus, these polymers have different properties and reactivities. Linear high MW PEI is usually solid at room temperature while branched PEIs are typically liquids at all molecular weights. All three forms are soluble in water, methanol, ethanol, and chloroform but insoluble in solvents of low polarity such as benzene, ethyl ether, and acetone.

Polyethyleneimine is a synthetic, water soluble, linear or branched polymer that has a high density of amino groups that can be protonated. At physiological pH, the polycation is very effective in binding to DNA and can mediate the transfection of eukaryotic cells. It is widely used in gene delivery system due to the ability to build a complex with DNA and support the release of endosomal through “proton sponge effect.” It is also facilitating the intracellular transport into nucleus. These properties succeed in polymer for MNPs coating and targeted therapy.