I am trying to transduce ARPE-19 cell line. I used Lipofectamine 3000 to produce my lentiviral vectors. My 1st attempt at transduction is unsuccessful.

• I have seeded 0.3 million cell per well in a 6 well plate. Is the number alright for transduction?
• I also used 01 ug/ml of puromycin for selection. Is the concentration too high?

But 5 days into the selection process, all cells in the transduced well are dead.

• I don't quantify the viral titer and used 2ml of of the viral particles. I am wondering if too much concentrated titer has killed the cells or not. Does anybody have some insights?

Any suggestion is welcome.