Preventing Contamination: You Can Do It

Unfortunately, many researchers have experienced that sinking feeling: the beginning signs that something is going wrong with their cell cultures, followed by an even worse feeling of confirming it. Identifying contamination and its source is a time consuming task, one that some of us have spent (too much) time on. And while preventing incubator contamination takes time as well, the end result—your viable work—is the payoff.

So is your laboratory doing everything possible to prevent contamination before it starts?

Want to learn more? Explore our on-demand webinar: Cell Culture Contamination: What You Don’t Know Can Cost You

Maintaining aseptic techniques

It’s the beginning of a new study. The lab is spotless. Every staffer is wearing gloves, coats—maybe even shoe covers and hairnets. You have new bottles of media and sterile consumables. The energy level and enthusiasm are high, and you’re ready to begin.

What does the lab look like a month later? Three months later? Six? Even if you’re dogged about some protocols, such as cleaning the incubators following manufacturer’s instructions, it’s easy to let others slip through. Are you working with only one cell line at a time? Are you being careful to avoid touching pipettes to other surfaces, or quarantining shared reagents and cells from other labs?

What’s more, conditions in the lab can change unknowingly, such as fungi or bacteria being introduced through the ventilation. Always wear gloves, yes; wipe down the working surface in the biological safety cabinet with 70% alcohol before and after use; and plan to clean the incubators at least once or twice a month. But also be sure to test for contamination regularly. Even with your best efforts, biological contamination can creep in unexpectedly and threaten your work.

Making the right choices in filtration

While you can’t always keep every contaminant out of your lab, filtration provides a last line of defense against contamination, keeping it from affecting the outcomes of your work.

Selecting the right filter from myriad choices can be a challenge. You’ll want to look at four factors:

1. filter type
2. pore size
3. filtration volume
4. filter material

Understanding exactly how filters work is a key to successful filtration. Membrane filters, the kind best suited to cell culture sterilization, trap contaminants using several methods. The most common is pore size, which is a critical aspect of your filter selection. Look for pore sizes of 0.2 microns or less to remove bacteria, or 0.1 or less to also exclude mycoplasma, a contaminant all the more nefarious because it is so difficult to detect.

More about preventing contamination

Want to learn more about preventing contamination in order to protect your cells and research? Find the on-demand Cell Culture Café webinar, Cell Culture Contamination: What You Don’t Know Can Cost You, in the Thermo Scientific Cell Culture Community.