Transfection is the process of introducing exogenous genetic material in the form of DNA or RNA into eukaryotic cells. The entry of this genetic material into the cell is allowed by the transient opening of pores in the membranes, it is then possible to introduce a plasmid, a small interfering RNA or other. Cells manipulated to accept a foreign nucleic acid are called competent cells. Transfection is not to be confused with transduction, which uses a different route of entry into the cell (through the use of a viral vector).