P.R.I.T.-ALI Technology for testing airborne substances

Figure: P.R.I.T®ExpoCube

The innovative and patented P.R.I.T. –ALI Technology enables the use of cell cultures and tissues for testing of inhalable substances from the most different sources under appropriate conditions according to the current state of scientific knowledge.

They make use of what is called air-liquid interface cultures, which guarantee maximum similarity of the in-vitro system and the real human situation. The effects of substances can be accurately characterized by analyzing a wide variety of cellular alterations. The cell-based test methods can be used with a large diversity of test substances, including chemical gases, volatile substances, pharmaceutical sprays, exhaust gases, fumes and many others.


Human, Experimental animals, Cells and tissues from target organs (primarily airways and skin)

Field of application: disease

There is a broad range of application areas for the testing of airborne substances by means of alternative in-vitro methods. Since test atmospheres can be collected from the most different sources, cell and tissue based studies on a broad range of topics and materials are possible:

  • Environmentally relevant atmospheres and mixtures
  • Occupationally relevant situations
  • Product-specific issues, such as worst-case scenarios of airborne pollutants being released as a result of defects
  • Chemical gases
  • Volatile substances and mixtures
  • Pharmaceutical products for inhalation administration
  • Cosmetic products

Endpoints/Outcome parameter

  • Toxicity
  • Genotoxicity
  • Inflammation
  • Immunomodulation
  • Irritation
  • Gene expression

Readout parameter

  • Electronical cell counter (viability, cell number, cell volume, cell size)
  • Tetrazolium salt conversion (WST, MTT XTT)
  • Lactate dehydrogenase Assay (LDH)
  • Neutral red Assay (NRU)
  • Alamar blue Assay
  • ATP Content
  • GSH Glutathione Assay
  • Reactive oxygen species (ROS)
  • Transepithelial resistance (TEER)
  • Cytokine release (e.g. IL-8, IL-4, IL-6, Il-1ß, TGF-alpha, RANTES, GM-CSF, MCP-1)
  • Micronucleus assay
  • Comet assay
  • Microarray analysis with Affymetrix GeneChip®

Quality management measures

  • Internal quality management;
  • Controls
  • Blinded data collection and evaluation
  • Randomization
  • Others (e.g. historic controls)


  • Switalla, S., Knebel, J., Ritter, D., Krug, N., Braun, A., Sewald, K. (2010). Effects of acute in vitro exposure of murine precision-cut lung slices to gaseous nitrogen dioxide and ozone in an air-lifted interface (ALI) culture Toxicology Letters 196 117-124

  • Switalla, S.; Knebel, J.; Ritter, D.; Dasenbrock, C.; Krug, N.; Braun, A.; Sewald, K.: Determination of genotoxicity by the Comet assay applied to murine precision-cut lung slices.
    Toxicology in vitro 27 (2013), No. 2, pp. 798-803

  • Ritter, D., Knebel, J (2014), "Investigations of the biological effects of airborne and inhalable substances by cell-based in vitro methods: fundamental improvements to the ALI concept", Advances in Toxicology Volume 2014, Article ID 185201

  • C. Brodbeck, D.Ritter , J. Knebel (2015) NAFEMS World Congress 2015, San Diego (USA), "Improvements of an Air-Liquid Interface In-Vitro Testing Method for Inhalable Compounds using CFD-Methods"