THP-1 cells are a human monocytic leukemia cell line cultured in suspension. They are widely used to model monocyte-tomacrophage differentiation. Occasionally, a small proportion may adhere to the flask surface during routine culture, which is normal.
Figure 1. Photomicrograph of Cells Showing Normal Growth Morphology
Minor adhesion (<20%)
Lightly shaking the flask will typically resuspend these cells. For passaging, transfer only the suspension cells and do not retain the adherent cells. Slight adhesion commonly results from prolonged static culture allowing cells to settle.
Excessive adhesion (>20%) or tightly adherent cells
Verify that culture vessels are made from untreated, low-attachment plastics to discourage adherence.
Confirm passage number; highpassage THP1 lines may deviate in phenotype and should be discarded and replaced from a lower passage vial.
Review culture conditions:
Medium: RPMI1640 + 10% FBS + penicillin/streptomycin + 0.05 mM 2-mercaptoethanol
Incubator: 37 °C, 5% CO₂ (i.e., 95% air / 5% CO₂)
General maintenance tips
Maintain cell density at 3–7 × 10⁵ cells/mL, ideally ~5 × 10⁵/mL
Leaving 1–2 mL of conditioned (spent) medium when refreshing improves growth.
Clumping can be mitigated by optimizing serum quality or concentration (up to 20%).
Recommended Yeasen Product for THP-1 Suspension Transfection
If you are performing transfection of THP1 cells (e.g., with siRNA or miRNA), Yeasen offers reagents optimized for suspension cell lines like THP1:
Hieff Trans™ in vitro siRNA/miRNA Transfection Reagent (Cat No. 40806ES)
A nonliposomal PEIbased reagent that supports up to ~80% silencing efficiency in suspension cell lines such as THP1, in serumcompatible conditions .
Summary Table
|
Issue |
Suggested Action |
|
Minor adhesion (<20%) |
Shake flask; transfer only suspension cells at passaging |
|
Excessive adhesion |
Use lowattachment flasks, verify passage number, review medium/additives |
|
Culture conditions |
RPMI1640 + 10% FBS + PS + 0.05 mM 2mercaptoethanol; 37 °C, 5% CO₂ |
|
Cell density |
Maintain 3–7 × 10⁵ cells/mL; use conditioned medium when passaging |
|
Transfection reagent |
Use Yeasen Hieff Trans reagents (Cat. No. 40805ES or 40806ES) |
Related Products
|
Product Name |
Specification |
Cat No. |
|
0.5 mL/1 mL |
40806ES02/03 |