Technical library

Yes. PromoCell human mesenchymal stem cells (hMSCs) can be expanded prior to differentiation.
The cells are cryopreserved at the end of the second culture. After thawing and seeding, they are therefore in passage 2 (third culture).
 
For optimal results, we recommend:

• Inducing differentiation no later than passage 5.

The differentiation potential of hMSCs decreases with increasing population doublings. Consequently, earlier induction of differentiation generally results in higher differentiation efficiency.

For optimal expansion, human CD34⁺ progenitor cells are cultured in PromoCell Hematopoietic Progenitor Cell Expansion Medium XF (C‑28021) supplemented with Cytokine Mix E (C‑39890) or an alternative cytokine cocktail suitable for progenitor cell expansion.
Cytokine Mix E contains the recombinant human cytokines TPO, SCF, Flt‑3 ligand, and IL‑3, which support robust proliferation of CD34⁺ cells.
 
Under these conditions:

• Strong expansion of CD34⁺ progenitor cells is typically maintained for approximately 2 weeks.
• The expansion factor of CD34⁺ cells is usually in the range of 75‑ to 200‑fold, depending on donor material and culture conditions.

PromoCell does not determine population doublings (PDs) for mononuclear cells cultured in Mononuclear Cell Medium (C‑28030).
 
Intended use of Mononuclear Cell Medium
PromoCell Mononuclear Cell Medium (C‑28030) is designed for short‑term maintenance only:

• Suitable for up to 48 hours after thawing
• Intended to keep human mononuclear cells (hMNCs) viable before downstream applications

It is not intended for long‑term expansion, and therefore no population doubling values are specified.
 
Why PDs are not defined

• Mononuclear cells are typically used in immunology, infection biology, hematology, and cancer research
• They consist of heterogeneous subpopulations (e.g. lymphocytes, monocytes)
• Population doublings depend entirely on subsequent culture conditions, which are application‑specific and not controlled by PromoCell

The recommended plating density after thawing or subculturing depends on the specific stem or blood cell type. Please consult the corresponding Instruction Manual and refer to the "Specifications" section for cell type-specific recommendations.

The recommended plating (seeding) density after thawing or subculturing depends on the specific cell type.
As a general guideline, a density of 5,000 cells/cm² is suitable for most human primary cells.
For cell type-specific recommendations, please consult the corresponding Instruction Manual. Recommended values can be found in the “Specifications” section.

The passage number of PromoCell Normal Human Cells upon arrival depends on the specific cell type.
The exact passage information can be found:

• in the Cell Instruction Manual under “Specifications”, and
• on the Certificate of Analysis (CoA) provided with each cell lot.

Information on the passage number used for testing cell type‑specific markers can usually be found in the Certificate of Analysis (CoA).

• For current CoAs, this information is listed under Results of Analysis → Identity and Purity → Test Method
• For older cell lots, it may be listed under Phenotypic Characterization
• For blood cells, marker analysis is performed directly after thawing, as these cells are not expanded in culture prior to testing
• Macrophages are typically analyzed 2-3 days after thawing and plating

When using PromoCell Mesenchymal Stem Cell Osteogenic Differentiation Medium with human mesenchymal stem cells derived from bone marrow (hMSC‑BM), the expected differentiation rate into the osteogenic lineage is approximately 70-100 %.
The actual differentiation efficiency may vary depending on factors such as donor variability, passage number, culture conditions, and experimental handling.

PromoCell Human Chondrocytes (HCH) can be expanded in standard monolayer culture using PromoCell Chondrocyte Growth Medium (C‑27101).
This medium is an optimized formulation supplemented with 10 % FBS and is suitable for efficient cell expansion.

De‑differentiation during monolayer culture
De‑differentiation of chondrocytes is a well‑known and unavoidable phenomenon during in vitro monolayer culture and typically occurs after approximately 2 weeks.
Despite this limitation, monolayer culture is necessary to expand chondrocytes to sufficient cell numbers.

Re‑differentiation using 3‑D culture systems
Once an adequate cell number has been obtained, the monolayer system can be replaced by a more complex 3‑D culture approach, such as:

• Culture in alginate beads or gels
• Use of degradable polymer scaffolds
• 3‑D spheroid culture

Under appropriate 3‑D conditions, re‑differentiation is induced, and chondrocytes resume the production of cartilage‑specific extracellular matrix (ECM) components.

PromoCell position
PromoCell does not offer a proprietary 3‑D culture system for chondrocytes.
However, 3‑D spheroid culture combined with Alcian Blue staining is used internally by PromoCell to characterize chondrocytes during quality control.
This procedure is very similar to the protocol used for chondrogenic differentiation of MSCs.

All PromoCell cell pellets (C‑14***) are prepared from Quality Control (QC)‑released cell lots. The majority of cell pellets are prepared after one passage in culture following thawing of the corresponding cryopreserved cells.
 
HUVEC and HUAEC

• Cells are P1 after thawing
• Cell pellets are therefore frozen at P2

Smooth muscle cells, keratinocytes, and epithelial cells

• Cells are P2 after thawing
• Cell pellets are therefore frozen at P3

Blood cells

• Blood cells are cryopreserved immediately after isolation (P0).
• Cell pellets are prepared directly after thawing, without any additional cultivation step.