Editing 293F Protein Production (section)

==== <br>Transfection<br><br>  ====

1. RPMI 1640 medium containing 25 mM HEPES and 4 mM glutamine (Lonza).<br>2. Pluronic® F-68 dissolved in water at a concentration of 2%. The solution is filter sterilized and stored at room temperature.<br>3. VPA (2-propyl-pentanoic acid, sodium salt) (Sigma-Aldrich) is prepared as a 500-mM solution in water, filter sterilized, aliquoted into sterile 50-mL tubes, and stored at −20°C. The working solution is maintained at 4°C. VPA is a known teratogen.<br> 

4. Linear 25 kDa polyethyleneimine (PEI) (Polysciences) is dissolved in water at 1 mg/mL at a pH of 7.0. When dissolving, lower the pH with 1 N HCl. When the PEI is in solution, the pH is increased to 7.0 with&nbsp; 1 N NaOH. The solution is filter sterilized, aliquoted into sterile 50-mL tubes, and stored at −20°C. It can be stored frozen for years as long as repeated freeze–thaw cycles are avoided.<br>5. Ex-cell® 293 medium without L-glutamine and phenol red <br>6. 50× L-glutamine–phenol red solution.<br><br>