Spinning the cells for 15 min at 350 x g has been proven and tested by PromoCell Research & Development. The QC department uses these settings during testing. Any lower centrifugation value (g-force and/or time) will lead to significant cell loss by means of non-sedimented; but intact; macrophages.
a) We usually perform macrophage differentiation in T75 flasks and 6-well plates. We haven't tested differentiation in smaller formats. But we assume it will be problematic to thoroughly wash the surface of the wells to remove non-adherent cells after the attachment phase. b) Detachment of the mature macrophages is possible but re-attachment can lead to significant cell loss (30-50%).
Please also keep in mind that working in 96/384 well-format has some inherent drawbacks (e.g.; evaporation of media; dry wells; etc.).
The Macrophage Detachment Solution (C-41330) directly affects the cell membrane. HSA in the Wash Buffer supports regeneration of the cell membrane and protects the cells during the critical phase directly after detachment from detrimental effects.
FBS (or BSA) can be substituted for HSA; however we do not recommend this as the FBS will lead to unpreferable immunologic stimulation of human macrophages.
The addition of EDTA to the PBS is to further augment the “anti-clumping” activity of the Ca2+/Mg2+ free PBS.
Most primary cells detach within 5-10 min at 37°C. Inactivation isn't required but we recommend to centrifuge the cell suspension to remove accutase and EDTA before replating the cells.
You can use our standard DetachKit (C-41200) to subculture the human nasal epithelial cells. Some customers still prefer to use our DetachKit-2 (C-41202) as it has a lower trypsin/EDTA concentration but tests in our cell culture lab haven't revealed any adverse effects when using C-41200.
Add undiluted accutase to the culture vessel (2 ml per 25 cm2)
Incubate at room temperature for 5-15 min or at 37°C for faster detachment
When the majority of the cells has detached; centrifuge the suspension and resuspend the pellet in fresh medium. In most cases no additional washes or neutralization steps are required.