Linearized polyethyleneimine PEI (molecular weight 40,000) is a highly charged cationic polymer that readily binds to DNA or other negatively charged biomacromolecules, making it a common and effective cell transfection reagent. In principle, PEI condenses DNA plasmid into positively charged complexes. The complexes can adhere to negatively charged cell surface residues, and then enters the cell through endocytosis.
As a transient transfection reagent, PEI has the advantages of high efficiency, low cost and relative stability, etc., which has been validated for a wide range of common cell lines including HEK-293, HEK293T, CHO-K1, HepG2 and Hela cell transfection. In HEK293 and CHO cell expression systems, PEI provides excellent transfection results at different sizes (from 96-well plates to 100 L bioreactors).