DEAE Dextran for biochemistry DEAE is the oldest transfection reagent known. The method of complexation of plasmid DNA with diethylaminoethyldextran has been published in 1968 by McCutchan. Positively charged DEAE binds negatively charged DNA to aggregates, which then bind to negtively charged surface structures of cell membranes. Uptake is done via endocytosis. This DEAE method needs only little amounts of DNA, while resulting in high transfection efficiency of up to 30 %. However, the cytotoxic effects caused by DEAE allow only transient transfections. The following cell lines are well transfectable: CV-1, BSC-1 and COS cells, and other stabile, insensitive cell lines. Stock solution: 50 mg/ml in H 2 O. Autoclave. End concentration: 1 mg/ml (transfection for 30-90 min.) or 250 µg/ml (transfection for up to 8 h)