FIG. 4.

Cyclic stretch increases the number of cells transfected. A549 cells were grown under static conditions for 24 hours before and 24 hours after transfection with pEGFP-N1 (“static”) or exposed to cyclic stretch for 24 hours before and after transfection with pEGFP-N1 (“stretch”). Transfections were performed using lipoplex or electroporation as described in Materials and Methods. Twenty-four hours after transfection, cells were fixed and GFP expression was visualized and photographed using the same exposure times for all conditions.