Transfection procedures and reagents have improved over recent years, but some degree of cell damage and labeling inefficiency persists. If your transfection protocols are giving disappointing results, some possible causes include:

• Reagent may not have been stored correctly. Check to ensure that accidental refreezing did not occur

• DNA quality or amount may have been insufficient. Determine appropriate lipid-to-DNA ratio empirically

• Cell medium may be contaminated with serum or antibiotics. Be sure that medium contains no growth enhancers or other additives