Transfection is the process of deliberate introduction of naked or purified nucleic acids (DNA or RNA) into eukaryotic cells. Transfection can be achieved by viral and non-viral treatments. Viral mediated treatments include introduction of DNA by viral injection, using either retrovirus, lentivirus, adenovirus, adeno-associated virus, and herpes simplex virus. Non-viral treatments include physical (electroporation, cell squeezing, nanoparticles, magnetofection) and chemical treatments.