In vitro air-liquid interface (ALI) exposure method to simulate in vivo inhalation exposure

Scope of the method

The Method relates to
  • Environment
  • Human health
  • Other
Alternative method for in vivo/human inhalation exposure. ALI exposure systems can be used to screen for human health impact of the following cases: Nano/ultrafine particles, Environmental/occupational compounds, Petroleum-derived substances,
The Method is situated in
  • Basic Research
  • Translational - Applied Research
Type of method
  • In vitro - Ex vivo
This method makes use of
  • Human derived cells / tissues / organs
Specify the type of cells/tissues/organs
Lung cells


Method keywords
  • in vitro and in vivo tool
  • in vitro
  • cell culture
  • lung
  • simulation
  • aerosol
  • (nano)particle
  • vapour
  • gas
Scientific area keywords
  • in vitro
  • lung disease
  • respiratory toxicology
  • toxicity
  • Biomarkers
  • inflammation
  • aerosol
  • vapour
  • gas
  • (nano)particle
Method description

VITO can offer expertise in animal-free methods for inhalation testing. VITO has an Air-Liquid Interface (ALI) platform with three ALI exposure modules: two commercial systems for bronchial studies and one in-house developed system for lower airway studies. At VITO ALI exposure modules, aerosol generation and online characterization instruments, and a battery of biological assays (e.g. TransEpithelial Electrical Resistance, cell viability/cytotoxicity, oxidative stress, and inflammatory response) can be used for screening of human health impact of e.g. Nano/ultrafine particles, Environmental/occupational compounds, Petroleum-derived substances, consumer products, pharmaceuticals (toxicity, efficacy, pharmacokinetics).

Lab equipment
  • Air-liquid interface exposure system(s) ;
  • (Nano)aerosol generation facilities :
  • - Condensation Monodisperse Aerosol generator,
  • - Electrospray Aerosol generator,
  • - Single and Six Jet atomizers,
  • - Solid Aerosol generator,
  • - and a Soot generator;
  • Dedicated cell culture laboratories and assay facilities for biological endpoint measurements.
Method status
  • History of use
  • Internally validated
  • Published in peer reviewed journal

Pros, cons & Future potential


Inhalation toxicity testing has traditionally been conducted using animals. Concerns related to the weak predictive ability as well as the use of animals, cost, time, and technical difficulty of in vivo inhalation resulted in the development of in vitro efficient and accurate, human-relevant lung cell-based methods to assess the potential hazards associated with xenobiotic exposure. The first in vitro inhalation studies were performed with submerged lung cell cultures. While these cultures are still widely used in in vitro pulmonary toxicity studies due to relative ease of handling, dispersion exposures are poorly representative of aerosol inhalation in humans. To overcome this, in vitro systems are developed for airborne exposure of lung cells at the air-liquid interface.


There are different ALI exposure systems on the market. No harmonized protocols are available.



Future & Other applications

Yes, ALI technology might be of relevant for biotech/pharma sector.

References, associated documents and other information


Frijns E et al. 2017. A Novel Exposure System Termed NAVETTA for In Vitro Laminar Flow Electrodeposition of Nanoaerosol and Evaluation of Immune Effects in Human Lung Reporter Cells. Environmental Science & Technology, 51 (9), DOI:10.1021/acs.est.7b00493

Patent application for NAVETTA product; Flatbed air-liquid interface exposure module and methods (EP16200571.4; 2016, CN201780072888.1; 2019)


Contact person

Sandra Verstraelen


Vlaamse Instelling voor Technologisch Onderzoek (VITO)
Flemish Region


Vlaamse Instelling voor Technologisch Onderzoek (VITO)