MedTec has developed a new line of in vitro exposure systems to satisfy the demand for in vitro toxicity testing. Our superior in vitro exposure systems simplify the process for conducting exposure of cells at the air-liquid interface. These systems were designed with the user in mind by providing a versatile design; small foot-print; and effective delivery of gases, vapors, particles and aerosols onto cultured cells.

SMALL FOOTPRINT - Our compact design allows for use on a benchtop, lab cart, or inside a hood.
EASY SETUP - Unpacking and setup of the system with all the connections takes just 20 minutes!
MINIMAL TRAINING - All operational parameters are preset, with easy to follow step-by-step procedures provided in the User’s Manual.
GAS EXPOSURES - Efficient delivery of gases onto cells.
PARTICLE EXPOSURES - Enhanced particle deposition is achieved with the use of electrostatic precipitation.
TEMPERATURE REGULATED - The heated enclosure houses the exposure chamber and maintains a 37°C environment.
HUMIDITY REGULATED - A unique humidifier warms and moistens the air to maintain cell viability and integrity intact. The humidifier does not dilute the test atmosphere.

No other commercial system has this feature!

CelTox Sampler


  • Combustion Emissions
  • Volatile Chemicals
  • Secondary Organic Aerosols
  • Cigarette & E-Cigarette Smoke
  • Bioaerosols
  • Nanomaterials
  • Dermal Exposures
  • Drug Delivery

MULTI-WELL FORMATS - Accommodates various multi-well formats using our custom multi-well plates or standard disposable plates.

Humidifiers - Maintaining a proper viable environment for the cultured cells during exposure is key for successful exposures. To avoid cellular damage due to desiccation, maintaining relative humidity levels above 75% at ~37°C is necessary. This means that moisture needs to be added to the sampled test atmosphere at ~37°C prior to exposing the cells. Humidifying the sampled air at room temperature is not sufficient. For this reason, the CelTox Sampler setup includes a temperature-regulated diffusion humidifier in-line upstream of the exposure chamber. What’s unique about our diffusion humidifiers is that they are a non-diluting humidification system that can add moisture to the sampled atmosphere without diluting the test atmosphere. This is especially important when trying to expose cells to complex mixtures containing both gases and particles because the physical-chemical equilibrium of the gases/particles is not altered.

Our standard diffusion humidifier is designed specifically to accommodate the 2.0 L/min flow rate of the CelTox Sampler. We also offer a smaller humidifier for ~1 L/min flow rates and do custom sizes if working with other systems requiring lower flow rates. The humidifiers can be customized with a variety of tube fittings easy integration into your experimental setups.

Dryers - While relative humidity levels above 75% at ~37°C are necessary to maintain a viable environment for the cells during exposure, these high humidity levels pose several challenges to the experimental setup and equipment downstream of the exposure chamber. Operating under these relative humidity levels means the Dew Point is 33-34°C so any wetted surface that’s below that temperature will cause condensation. This condensation can accumulate fast and block the flow. For this reason, all the CelTox Sampler components and accessories are housed inside our Heated Enclosure. If any other equipment (e.g., Vacuum pump, Mass Flow Controllers, SMPS, etc.) is being used downstream, then that equipment runs the risk of failure or damage due to condensation.  For this reason, the CelTox Sampler setup includes an in-line dryer downstream of the exposure chamber. Our dryers are filled with silica beads that change color as they absorb moisture. With our clear tube housing, the user can easily observe when the beads are saturated and require changing. The silica beads can be reactivated in an oven so they can be used again. We offer a standard dryer and a diffusion dyer. In the standard dryer, the sampled test atmosphere is directly touching the silica beads. In our diffusion dryer, the sampled test atmosphere does not touch the silica beads directly.

Our standard and diffusion dryers are designed specifically to accommodate the 2.0 L/min flow rate of the CelTox Sampler.  For higher flow rates, we offer a large volume standard and diffusion humidifier. If using a nebulizers or atomizer, for example, to generate an aerosol, our large volume diffusion humidifier can be used in the particle generation setup to dry the aerosol before delivering it to the CelTox Sampler.

Scrubbers - The relatively small foot-print of the CelTox Sampler allows it to be set up inside a chemical hood, on top of a laboratory bench or a cart. In all setups, the user must ensure that there is an exhaust vent nearby to safely exhaust the test atmosphere. In the event that an exhaust vent is not available, some type of pollutant control media should be used to avoid accidental exposure to the users in the lab. We offer a scrubber option in two sizes. Our scrubbers are filled with activated carbon filters. These scrubbers can be refilled with new filters as needed. It is important to note that users should adequately test these scrubbers with their test atmosphere independently to ensure that pollutant removal is adequate and to determine the operational life of the filters.

A vehicle control exposure is always recommended using clean, filtered air for comparison against the test atmosphere. Some labs might use a Zero Air gas cylinder, while others might have a clean, filtered house air that supplies the entire lab. If these are not an option, our scrubbers can be used at the at the inlet to generate a clean, filtered air source directly from your room air. Particle filters can be added into the scrubber to ensure both particulates and VOCs are being removed from the sampled. Additionally, the room air RH can also be removed to ensure a reproducible clean air source. Our scrubbers can also be turned into a Dual Scrubber/Dryer simply by filling the tube housing partially with activated carbon filters and the rest with silica beads.

Temperature & RH Sensor - Maintaining a proper viable environment for the cultured cells during exposure is key for successful exposures. To avoid cellular damage due to desiccation, maintaining relative humidity levels above 75% at ~37°C is necessary. The CelTox Sampler comes equipment with a Heated Enclosure and a Diffusion Humidifier to achieve these conditions. Mounted inside the Heated Enclosure immediately after the Exposure Chamber is an in-line temperature and humidity sensor that can be used to monitor these conditions. Our standard sensors are housed in a plastic Delrin body with plastic barb fittings, and a digital sensor with an RS-232 connection. Data can be logged using the supplied software on any windows computer. These sensors can also be used with LabView software.

These small, in-line sensors can be customized per customer’s needs. The digital sensor can be exchanged for an analog sensor where the user will supply their own power input voltage and use a data acquisition system to log the output voltages to obtain the temperature/RH values. The users can also request a stainless steel body and any type of tube connectors, such as Swagelok fittings.

Tube Fittings - Our humidifiers, dryers, scrubbers, and Temp/RH sensors can be used in other setups and systems. The dryers can be customized with a variety of tube fittings easy integration into your experimental setups.

Literature & Talks

  • The predecessor to the CelTox Sampler was named the Gillings Sampler. The manuscript "The Gillings Sampler – An electrostatic air sampler as an alternative method for aerosol in vitroexposure studies" can be found here.
  • The CelTox Sampler's unique temperature and humidity regulation is critical to avoid cytotoxicity due to cell desiccation. The manuscript "Regulating temperature and relative humidity in air–liquid interface in vitrosystems eliminates cytotoxicity resulting from control air exposures" can be found here.
  • In 2018,  a symposium entitled "In VitroTest Methods to Model Local Respiratory Effects after Exposure to Pulmonary Toxicants: Not Just Smoke and Mirrors" was held at the Society of Toxicology Annual Meeting. Here, a talk entitled "Understanding Air-Liquid Interface Cell Exposure Systems: A Comprehensive Assessment of Various Systems under Identical Conditions" was presented. Data in this talk clearly demonstrates the superior performance of the Gillings Sampler (the predecessor prototype of the CelTox Sampler). A manuscript on this study is in preparation. This talk can be found here.


The vision and concept of the CelTox Sampler originated at the University of North Carolina at Chapel Hill. Dr. Jose Zavala developed what is now the CelTox Sampler during his graduate studies at UNC-Chapel Hill under the direction of Drs. Harvey Jeffries, Ken Sexton, and Will Vizuete. This technology captured media attention in 2013 when National Public Radio published a story on this system. The article can be found here and you can listen to the story next.

Audio Title

A short cartoon was developed by NPR summarizing the vision and concept of the CelTox Sampler. Enjoy!

Interested in air-liquid interface exposures?

Jose Zavala, Ph.D.

For more information contact Jose directly via email, Linkedin or send us a message via the site.
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