In molecular biology, even the smallest breakthroughs can dramatically expand our understanding of life. When it
Where Does Contamination Come From?
Contamination in cell culture can arise from several sources:
Physical contamination: radiation, improper temperature, or poor environmental conditions.
- Chemical contamination: impurities in media, serum, or water; endotoxins; plasticizers; detergents.
- Microbial contamination: the most common issue, including bacteria, fungi (yeast and mold), viruses, mycoplasma, or even cross-contamination from other cell lines.
Common Types of Microbial Contamination
1. Bacterial Contamination
- Shape: Spherical, rod-shaped, or spiral.
- Medium appearance: Turns yellowish.
- Microscope view: Large numbers of moving particles, often resembling “quicksand.”
What to do:
- For mild contamination: wash with PBS and treat with 10× penicillin/streptomycin (temporary solution).
- For heavy contamination: discard the cells, disinfect the incubator and work area.
Figure 1. Representative image of bacterial contamination showing rod- and cocci-shaped cells with high motility and medium turning yellow.
2. Yeast Contamination (Fungal)
- Shape: Round or oval, sometimes budding.
- Medium appearance: Clear at first, yellowish over time.
- Microscope view: Single round cells, sometimes budding into smaller particles.
What to do:
Best practice: discard the culture.
Possible rescue (not recommended for routine work): wash with PBS, replace media, and add amphotericin B (toxic to cells) or 300 μg/mL fluconazole. If contamination is controlled, switch to 150 μg/mL for 2–3 passages.
Figure 2. Representative image of yeast contamination showing round or oval budding cells; medium remains clear initially and turns yellow at later stages.
3. Mold Contamination (Fungal)
- Shape: Filamentous hyphae.
- Medium appearance: Initially unchanged, later cloudy or fuzzy.
- Microscope view: Thin, thread-like structures, sometimes dense spore clusters.
What to do:
- Discard contaminated cells immediately.
- Wipe the incubator with 70% ethanol, then clean with a strong disinfectant (e.g., benzalkonium chloride).
Add copper sulfate to the incubator water pan to discourage fungal growth.
Figure 3. Representative illustration of mold contamination characterized by filamentous hyphae and cloudy medium at advanced stages.
4. Mycoplasma Contamination
- Appearance: Tiny black dots under the microscope.
- Medium: No obvious color change.
- Microscope view: Slow cell growth, abnormal morphology.
How to confirm: Use a mycoplasma detection kit.
What to do: Treat with mycoplasma removal reagents; use prevention kits for long-term protection.
Figure 4. Representative illustration of mycoplasma contamination with small dark particles, slow cell growth, and abnormal cell morphology without obvious medium color change.
Cell culture contamination is frustrating, but it’s also preventable. Strict aseptic technique, regular cleaning of incubators and biosafety cabinets, and periodic testing for mycoplasma can go a long way in keeping your cells healthy. When contamination does occur, don’t hesitate to discard and start fresh—sometimes saving a contaminated culture costs more in the long run.
Tips for Preventing Cell Culture Contamination
- Keeping your cultures clean is always easier than trying to fix contamination later. Here are some practical tips to reduce the risk:
- Master aseptic technique: Always work in a sterile biosafety cabinet, avoid unnecessary movements, and keep reagents and tools covered.
- Use quality reagents: Choose trusted suppliers for media, serum, and supplements to minimize chemical or microbial contaminants.
- Stay consistent with cleaning: Regularly disinfect incubators, water pans, and work surfaces. Replace water in CO₂ incubators weekly, and consider adding antifungal agents (e.g., copper sulfate).
- Aliquot reagents: Split media, serum, and supplements into smaller working volumes to avoid repeated freeze–thaw cycles and reduce cross-contamination.
- Wear protective gear: Gloves, lab coats, and sleeves keep both your cells and you safe from contaminants.
- Quarantine new lines: When you bring in a new cell line, test it for mycoplasma and grow it separately before mixing with existing cultures.
- Test for mycoplasma regularly: Every 1–2 months is a good standard, especially in shared lab environments-MycAway™ Plus-Color One-Step Mycoplasma Detection Kit (2G, 30 mins).
- Don’t try to rescue at all costs: Sometimes discarding and starting fresh is the smartest and safest choice.
Related Product
|
Catgory |
Application |
Name |
Cat. No. |
Size |
|
Mycoplasma Detection
|
Daily inspection |
40615ES25/60 |
25/100 T |
|
|
Daily inspection |
40614ES10/20 |
10/20 assay |
||
|
Product release inspection; Daily inspection |
40619ES25/60 |
25/100 T |
||
|
Mycoplasma Removing |
For cultured cells |
40607ES01/03/08 |
0.1/1/5×5 ml |
|
|
For operating tables and cell culture rooms |
MycAwayl™ Spray (Ready-to-use) |
40605ES02/03/08 |
1/2/10×500 mL |
|
|
Mycoplasma Prevention
|
For cultured cells |
MycAway™ Prophylactic (2000×) - Mycoplasma Prevention Reagent |
40608ES03/08 |
1 mL/5×1 mL |
|
For incubator water trays |
MycGuard™-1 Solution (100×), for Disinfecting Water Bath of CO2 Incubator |
40609ES60 |
100 mL |
|
|
For water baths |
MycGuard™-2 Solution (500×), for Disinfecting Ordinary Water Bath |
40610ES60 |
100 mL |