Ham's F-12K, Custom pH

FAQs

• Q:1 My cells are growing very slowly. What could be the cause of this?

  Answer

  Please see some common reasons below, and solutions to the issue: - Growth medium is not correct: Use pre-warmed growth medium as recommended by the supplier. - Serum in the growth medium is of poor quality: Use serum from a different lot. and choose good quality serum to ensure nutrition. - Cells have been passaged too many times: Use healthy, low-passage number cells. - Cells were allowed to grow beyond confluency: Passage mammalian cells when they are in the log-phase before they reach confluency. - Culture is contaminated with mycoplasma: Discard cells, media, and reagents. Obtain new stocks of cells, and use them with fresh media and reagents.

• Q:2 What factors can contribute to rapid cell death/culture failure?

  Answer

  There are a number of events that can contribute to this: 1. Incorrect CO2 levels:Monitor the level of CO2 manually with a Fyrite kit, available from Bacharach. Check if the manual readings concur with the readings displayed on the incubator. If the incubator has a trace readout, check the printout for fluctuations in CO2 level. Check the settings to ensure that CO2 levels are set at appropriate levels for your cell line (usually between 5 and 10%). Check line connections frequently for leaks. Avoid frequent opening and closing of incubator doors. 2. Temperature fluctuations in the incubator:Monitor the temperature of incubator with a good thermometer inside the incubator. 3. Amphotericin B or other preventive antibiotics/antimycotics are present at toxic concentrations:Use at recommended levels. 4. Humidity is incorrect:Check the water level in the water pan. Humidity is vital to appropriate gas exchange for many types of cells and media. 5. Incorrect osmotic pressure in medium:Check osmolality of complete medium. Most mammalian cells can tolerate an osmolality of 260 to 350 mOsm/kg. Additions of reagents such as HEPES and drugs may affect osmolality. 6. Contamination by microorganisms:Bacterial and fungal contaminations are usually easily visible; symptoms of mycoplasma contamination are more subtle, and careful monitoring of culture morphology and regular testing are necessary to detect this type of contamination. 7. Inappropriate medium is being used:Double-check that the medium used is appropriate for your cell type and culture application. For example, ensure that the medium being used for serum-free culture is actually designed for serum-free culture; make sure that appropriate selective drugs are used at appropriate levels; check the expiration dates for the reagents being used; and store medium at appropriate temperatures in the dark.