I am interested in transfecting HEK293 cells with a BAC. One paper suggests using 24 ug of DNA to transfect a 55-cm^2/10 ml culture plate. I am using an assay optimimzed for a 96 well plate so I am interested in scaling down the amount of DNA.
If I consider by volume: I will be going from 10 mL to 100 uL, scaling down by a 1/100, suggesting 0.24 ug of DNA.
If I consider by cell number: I will be going from 10^7 cells to 10^4 cells, scaling down by 1/1000, suggesting 0.024 ug of DNA.
If I consider by cell concentration: I will be going from 10^6 cells/mL to 10^5 cells/mL, scaling down by 1/10, suggesting 2.4 ug of DNA.
What factor should I scale down by? I want to say that it's volume but I don't really know why.
Thank you for any help or suggestions!