Transfection reagent is the chemical compound used to achieve transfection (i.e. introduce nucleic acid into eukaryotic cells). Transfection reagents, such as Transfectamine™ 5000, are positively charged and attract the negatively charged DNA to form a positively charged polymer, which can interact with negatively charged cell membrane which enables the uptake of this polymer into the cell. The polymer then travels to the cell nucleus and releases (transfects) the DNA.