Cell Locker System for CO2 Incubators

Highlighting Technical Information

TechNotes
How does a Thermo Scientific Cell Locker System
isolate cell cultures and projects in a CO2 incubator,
protecting them from cross-contamination?
Cell culture contamination is a concern for any lab. The Thermo Scientific™ CellLocker™ System consists of six sealed chambers fitted with 0.2 µm membranefilters. These chambers prevent transmission of microorganisms but allow exchangeof temperature, gases and humidity inside a CO2 incubator. The Cell Locker System
isolates sensitive cells, new cultures or individual projects in separate chambers
inside a single incubator.
In a Thermo Scientific Heracell VIOS 160i or Thermo Scientific Forma Steri-Cycle
i160 CO2 incubator, the HEPA system filters the entire incubator air volume toachieve ISO Class 5 cleanroom air quality. The Cell Locker System further protectsfrom cross contamination by dividing the incubator into six individual chambers.
Each Cell Locker is effectively a quarantine chamber.
The dual 0.2 µm membrane filters on each Cell Locker are hydrophobic, oleophobic
and prevent transmission of even small microorganisms when filtering air. To confirmthis prevention, the Cell Locker System was independently tested with circulating
microorganisms to prove that microorganisms cannot pass through the membranefilter to any Cell Locker.
An individual Cell Locker can be placed inside any CO2 incubatorand the complete Cell Locker System offers additional benefits ofenvironmental stability and flexibility.

What tests were performed?
The retention abilities of our microporous membranefilter are about ten times greater when filtering air thanwhen filtering liquid1. Thus, the Cell Locker filter offers
an effective 0.02 µm pore size, preventing transmissionof all microorganisms. However, we wanted to provide
proof by independent tests. Selected microorganisms
were distributed into the air stream in a Thermo ScientificHeracell VIOS 160i CO2 incubator equipped with the six
chamber Cell Locker System. The Heracell VIOS incubators
feature a HEPA filtration system that delivers ISO Class 5cleanroom conditions, but the HEPA filter was not used
for these tests so that the test microorganisms would
freely circulate.
To spread the microorganisms throughout the CO2
incubator and the Cell Locker System, a nebulizer drivenby pressurized air distributed either Staphylococcus aureus
or Mycoplasma orale. S. aureus are as small as 0.5 µm
and M. orale are as small as 0.1 µm. These are common
cell culture contaminants and their size makes themexcellent test subjects for our purposes.

Microorganism Tested

Sterile Petri dishes with the appropriate growth agar wereplaced inside the incubator, positioned outside and inside
the Cell Lockers, with a total of 24 dishes inside and 48
dishes outside the chambers. The dishes were uncovered
just before commencing the test and the nebulizer wasswitched on for one hour to circulate the bacteria. After thenebulizer was switched off, the dishes were covered andincubated 1-14 days at 37 ˚C. As shown in Table 1, the agar
dishes outside the Cell Lockers were filled with bacteria
but the agar plates inside the Cell Lockers remained sterile,
showing no growth of any kind.
Summary:
Thermo Scientific Cell Lockers and Thermo Scientific Cell
Locker Systems provide an effective isolation of cultures andprojects, preventing microbial cross-contamination in aCO2 incubator.
Boomus M. Bacteria and virus retention in air by microporous membrane. Medical Device& Diagnostic Industry Magazine, 2006
1Total Circulated

Total Outside Cell Lockers

Total Inside Cell Lockers

Staphylococcus aureus ATCC 6538

9.6 x 104

TNTC*

0**

Mycoplamsa orale DSM 25590

9.3 x 104

TNTC*

0**

*TNTC = too numerous to count. For each test, 48 Petri dishes containing appropriate growth agar were placed open on
top of the Cell Lockers.
**A total of 24 agar-containing Petri dishes were placed open inside the Cell Lockers. All showed zero growth.

Table 1: Test results demonstrate that circulating microorganisms are unable to enter Cell Lockers.
Each test was performed 3 times with the complete Cell Locker System (6 Cell Lockers) inside aHeracell VIOS 160i CO2 incubator with no HEPA filter present.

Find out more at thermofisher.com/co2
For Research Use Only. Not for use in diagnostic procedures.
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