The solution is acidic and stable at 4 C, but its stability decreases if buffered. The proton sponge effect of the complex buffers the acidic pH of the endosome. DNA should be sterile and free of any contaminant such as endotoxins. The cells should not be confluent or at stationary phase at the time of transfection. See Table 1 below for growth areas of tissue culture vessels.
Actual value depends on cell type.
The required amount of ExGen 500 depends on the amount of DNA and the number of equivalents needed. One equivalent represents the amount of ExGen 500 required to neutralize the negative charges of the DNA phosphate groups. Subsequent optimization may further increase the transfection efficiency in your particular application depending on the cell line and the gene expressed. Previously it has been shown that transfection efficiency is significantly decreased by the addition of serum to the incubation medium. The following protocol is for transfection of adherent cells in a 24-well plate.