In addition to proper cell handling and using culture media optimized for long term culturing of hepatocytes (Lonza Basal medium supplemented with BulletKit), we recommend separating the healthy hepatocytes from the dead cells and debris in the Nucleocuvette™ plate after Nucleofection. This can be done by adding to each well, 180ul Ficoll solution (25% Ficoll in Plating medium Lonza Basal Medium (Cat.No.:CC-3198) supplemented with BulletKit) and centrifuging the cells in the Nucleocuvette for 4 minutes at 75xg (No brake). Discard 150ul of the supernatant without disrupting the cell pellet, and add 50ul of warm plating medium to resuspend the cells carefully.