Direct in vitro Exposure Methods – The Future, Now!

Within inhalation toxicology, two main aspects are currently gaining importance:

  • The move towards in vitro studies to reduce or replace animal experiments
  • Analysis of native atmospheres by taking into account the actual exposure situation

Special exposure technologies, in particular the CULTEX® exposure modules, are able to satisfy such requirements. Today’s emphasis increasingly focuses on the human health impact of inhaled compounds. Reflecting the methodological difficulties of testing air contaminants in their natural gaseous or aerosolized state, there were previously no generally accepted techniques for exposing cells or bacteria effectively under such conditions.

Toxicological analysis under realistic atmospheric conditions

We therefore developed our high-end direct exposure equipment, the so-called CULTEX® system, which enables the treatment of adherent growing mono- and co-cultures, 3D cell constructs as well as bacteria with native atmospheres using air-liquid interface culture techniques. Unlike other exposure systems, this allows the reproducible testing of actual, environmentally-relevant gases without changing their physical and/or chemical properties. Customized systems for medium and gas supply ensure the nutrification and direct gas contact to the exposed cells grown on microporous membranes. The system offers the added advantage of being independent of a cell culture incubator, creating the option of analyzing any relevant gas or mixture directly under in- and outdoor conditions.

Reproducible results

The toxicological investigation of emissions from combustion processes in vitro, a burden both to the environment as well as to indoor atmospheres, was considered to be problematic and previous standard approaches have been limited to individual substances or synthetically generated model mixtures. These samples only poorly reflect the composition of the aerosols actually present in the real world. The ideal solution is to analyze such atmospheres in their native composition, in order to gain true insights into or indicators of their cytotoxic and mutagenic capacity. In response to this situation, we developed and established a new experimental method for the direct exposure of cultivated cells in the patented CULTEX® systems.

This innovative technique stands out in particular for the following reasons:

  • A reproducible and direct gas-cell contact between cells cultured on microporous membranes and the test atmosphere.
  • Nutrification of the cells through the membrane, avoiding interaction between reactive compounds of the test atmosphere and medium components.
  • Pressureless sample taking, in which the test atmosphere is passed over the test cells under predefined conditions.