<p><b>Copyright information:</b></p><p>Taken from "Electroporator with automatic change of electric field direction improves gene electrotransfer "</p><p>http://www.biomedical-engineering-online.com/content/6/1/25</p><p>BioMedical Engineering OnLine 2007;6():25-25.</p><p>Published online 2 Jul 2007</p><p>PMCID:PMC1941843.</p><p></p>microscope. Symbolic picture (c) was made for better representation of the observed shading effect. Drawn shapes represent cells and black areas represent regions of permeabilized membrane where DNA interacts with cell membrane. Symbols on the right represent electric field protocol used