Technical library

No. The fetal bovine serum (FBS) supplied in PromoCell culture media is not heat‑inactivated. 

In principle, both liquid‑phase and gas‑phase storage of cryopreserved cells in liquid nitrogen are acceptable. Each option has specific advantages and limitations.

Liquid phase storage

• Provides a constant temperature of −196°C
• Allows for a longer storage time and higher vial capacity
• However, it poses a risk of contamination.

Gas phase storage

• Considered very safe with regard to contamination
• Temperature is slightly higher and less uniform than in the liquid phase
• Shorter holding time and reduced vial capacity compared to liquid‑phase storage

Yes. PromoCell chondrocytes are derived from patients (approximately 40–85 years of age) undergoing total hip or knee joint replacement surgery, most commonly due to osteoarthrosis.
Cartilage tissue showing macroscopic lesions is excluded and not used for cell isolation, ensuring that the chondrocytes are derived from macroscopically unaffected cartilage.

The amount of medium required per vial of HUVEC can vary considerably and depends on several factors, including:

• Growth characteristics of the cells
• Size and type of tissue culture vessels used
• Split (dilution) ratios during subculture
• Frequency of medium changes
• Type of experiments performed

Because of this variability, exact quantities cannot be specified.
 
Rough guideline
As a general estimate, approximately 1–2 bottles of medium (500 ml each) are typically required to expand one vial of HUVEC to ~15 population doublings.

PromoCell’s Osteoblast Basal Medium (C‑27010) is an optimized medium formulation developed specifically for the culture of human osteoblasts.
The exact composition of the basal medium is proprietary and therefore not disclosed.

Yes, differentiated adipocytes can generally be split.
However, it is important to understand the biological limitation of these cells:

• Loss of proliferative capacity after differentiation: Once adipocytes are fully differentiated, they no longer proliferate. As a result, the culture cannot be expanded further after splitting.
• Implications for experimental planning: Although trypsinization and passaging are technically possible, this step does not increase cell numbers and may introduce unnecessary stress to the cells. In addition, we have observed in internal tests that, after detachment, freezing/thawing, and re‑plating of differentiated adipocytes, the lipid vesicles are no longer visible.

For this reason, it is recommended to plate the cells directly into the required culture vessels (e.g. multiwell plates) before initiating differentiation, so that splitting after differentiation is not necessary.

Cell source
PromoCell Normal Human Follicle Dermal Papilla Cells (HFDPC) are isolated from the hair papilla of normal human scalp hair follicles. Dermal papilla cells in adult hair follicles play a key role in dermal-epidermal interactions, which regulate:

• hair production, and
• hair growth cycle events.

Culture characteristics

• HFDPC are cryopreserved at passage 2. 
• When cultured in PromoCell Follicle Dermal Papilla Cell Growth Medium (C‑26501), they can be propagated for at least 10 population doublings
• Typical population doubling times: approximately 20–36 hours

Seeding density and passaging

• Recommended seeding density (after thawing or trypsinization): 5,000-10,000 cells/cm²
• Using a 1:4 split ratio, 4-5 passages can typically be performed.

When you purchase a proliferating culture of human osteoblasts (C‑12760):

• The T25 flask contains more than 500,000 cells at the time of shipment.
• Once the culture reaches subconfluency, you can expect approximately

750,000 to 1.1×10⁶ cells per T25 flask, depending on the cell lot.

The PromoCell Osteoblast Growth Medium (C‑27001) is designed to primarily support the proliferation of normal human osteoblasts.
 
Medium composition and function
The medium consists of Osteoblast Basal Medium supplemented with 10% (v/v) fetal calf serum (FBS). It does not contain recombinant growth factors. It also does not include osteogenic differentiation factors, such as dexamethasone or β‑glycerophosphate. As a result, the medium maintains osteoblasts in a proliferative state rather than actively inducing differentiation.
 
Why no differentiation factors are included
Many users employ the Osteoblast Growth Medium as a flexible baseline medium to:

• Test their own chemical compounds, growth factors, or hormones
• Study the effects of physical strain or shear stress on osteoblast function and differentiation

The absence of predefined osteogenic supplements allows for experimental customization.
 
Induction of mineralization
To specifically induce osteogenic differentiation and mineralization, PromoCell offers Osteoblast Mineralization Medium (C‑27020).

Yes. PromoCell provides a validated differentiation protocol for Human White Preadipocytes (HWP), which is described in the Instruction Manual of the respective media.

Recommended differentiation workflow and time frame

• Expansion phase
  • Grow HWP in Preadipocyte Growth Medium (C‑27410) until complete confluence is reached.
  • This phase typically takes approximately 1 week.
  • Change medium 2–3 times per week.
• Induction of differentiation
  • Aspirate the Growth Medium.
  • Add Preadipocyte Differentiation Medium (C‑27437) for 72 hours.
  • Aspirate the Differentiation Medium and switch to Adipocyte Nutrition Medium (C‑27438).
• Differentiation and maturation
  • Cells begin to accumulate lipid droplets, which can be visualized by light microscopy.
  • The differentiation process usually takes 1-2 weeks.
  • Change medium 2-3 times per week.
  • Differentiated adipocytes can be maintained in Nutrition Medium for up to 4 weeks. However, cell lysis and detachment commonly occur after approximately 3 weeks.

Important note
For optimal differentiation efficiency, we strongly recommend performing differentiation experiments at low population doubling (PD) numbers, ideally below PD 4-5, corresponding to a maximum of one passage after thawing.