Radial Flow System for cell-based exposure

This is a high-end exposure system for the direct exposure of cell culture inserts or Petri dishes. The modular system consists of two main parts, the aerosol-guiding module and the sampling module housing the cell culture inserts, or Petri dishes.

The aerosol-guiding module can be fitted tightly to the sampling module, thus realizing a close connection between the two parts before exposure. The sampling module houses three cell culture inserts (or Petri dishes), which can be separately supplied with medium.

An optimal installation of the CULTEX® LTC module inside an incubator can be achieved by using the special designed CULTEX® LTC Rack. It takes up to four modules, which can be run in parallel. The construction guarantees a horizontal position of the cultivation unit thus providing comparable medium levels in all culture inserts.An optimal installation of the CULTEX® LTC module inside an incubator can be achieved by using the special designed CULTEX® LTC Rack. It takes up to four modules, which can be run in parallel. The construction guarantees a horizontal position of the cultivation unit thus providing comparable medium levels in all culture inserts.

The modular concept of CULTEX® product solutions allows simple, investment-safe upgrading of the CULTEX® RFS with a wide range of enhancement systems:

  • CULTEX® EDD Module – well-engineered Electrical Deposition Device to increase the deposition efficiency for micro-sized and nano-sized particles
  • CULTEX® DG Module – our Dust Generator recommended as essential peripheral equipment for the exposure of cells to dry powder aerosols
  • CULTEX® HyP Module – our high-precision Hydraulic Press for the production of homogeneous dust cakes for uniform aerosol generation and reproducible results
  • CULTEX® Insertomat – a helpful device for the excision of the delicate microporous membranes from cell culture inserts for histopathology
  • CULTEX® Process Plate – facilitates the processing of Falcon® and Transwell® inserts


CULTEX® RFS – the recipient of several awards

The cell culture reactor CULTEX® RFS has already received the Dr. Rudolf Eberle Prize, the innovation prize awarded by the State of Baden-Württemberg. As emphasized in the laudatory speech, this prize represents the recognition of new technological developments of the highest standard. The precision system manufactured from the highest quality materials is in the meantime also being successfully used in a project to test the method for direct exposure of cells, in which various research groups are assessing the stability, reproducibility and validity of the method on different sized particles up to nanoparticles, to establish fundamental legally recognized principles for a testing system.

Exposure systems

General features

  • Direct exposure technology at the air-liquid interface of
    cell cultures
  • Cellular systems: cell lines and primary cells from the
    respiratory tract as mono- or co-cultures
  • Test compounds
    • Gases
    • Particles (fine to nanoparticles)
    • Complex mixtures (e.g. tobacco smoke)
  • Application areas
    • Industrial chemicals (particulate & gaseous compounds)
    • Consumer products
    • Tobacco smoke
    • E-cigarette vapor
    • Pharmaceutical and therapeutic products
    • Pesticides
    • In- and outdoor analysis
  • Clients
    • Universities
    • Regulatory Bodies
    • Military
    • Pharmaceutical, chemical and tobacco industry
    • Contract research laboratories

Basic principles of the exposure systems

Module design

  • Inlet adapter
  • Exposure top – Aerosol guiding module
  • Base module – Sampling module
  • Socket module
  • Locking module


  • Use of the system with or without dilution

Test atmosphere

  • One sampling point
  • Radial flow system
  • Homogenous distribution of the test atmosphere to the surface of the cells
  • Reproducible deposition of the particles on the cell surface
  • Establishment of dose-response relationships
  • Repeated exposure studies

Biological test system


  • Maintenance of cell viability
    • 37° C by a temperature-controlled flow of water
    • Medium supply from below the insert membrane
      (static, intermittent, continuous)
  • Application of 6.5 mm, 12 mm and 24 mm Falcon®
    or Transwell® inserts via special adapters


  • Special adapter for 35 mm Petri dishes for running a modified Ames assay

Air-liquid interphase – in vitro exposure

Exposure systems – CULTEX® RFS – Radial Flow System

  • Flexible design of the exposure top with aerosol inlets for
    commercial available membrane inserts (Falcon®/Transwell®)
    of different size and 35 mm Petri dishes
  • 3 exposure positions
  • Individual exposure chambers (3 membrane inserts)
  • Tempering of the exposure chambers
  • Individual medium supply of the independent exposure
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  • August 1, 2017

    Exp Toxicol Pathol. 2017 Jul 5;69(6):359-365

    “Improvement of the CULTEX® exposure technology by radial distribution of the test aerosol.”

    M. Aufderheide, W.D. Heller, O. Krischenowski, N. Möhle, D. Hochrainer

    The exposure of cellular based systems cultivated on microporous membranes at the air-liquid interface (ALI) has been accepted as an appropriate approach to simulate the exposure of cells of the respiratory tract to native airborne substances. The efficiency of such an exposure procedure with regard to stability and reproducibility depends on the optimal design at the interface between the cellular test system and the exposure technique. The actual exposure systems favor the dynamic guidance of the airborne substances to the surface of the cells in specially designed exposure devices. Two module types, based on a linear or radial feed of the test atmosphere to the test system, were used for these studies. In our technical history, the development started with the linear designed version, the CULTEX® glass modules, fulfilling basic requirements for running ALI exposure studies (Mohr and Durst, 2005). The instability in the distribution of different atmospheres to the cells caused us to create a new exposure module, characterized by a stable and reproducible radial guidance of the aerosol to the cells. The outcome was the CULTEX® RFS (Mohr et al., 2010). In this study, we describe the differences between the two systems with regard to particle distribution and deposition clarifying the advantages and disadvantages of a radial to a linear aerosol distribution concept.
    Copyright © 2017 Elsevier GmbH. All rights reserved.

    Air-liquid-interface; CULTEX® RFS; Deposition efficiency; Inhalation exposure systems

    Read more on Science Direct

  • May 1, 2014

    Journal of Applied Toxicology 2014; 34:506-515

    “Direct exposure at the air-liquid interface: evaluation of an in vitro approach for simulating inhalation of airborne substances”

    J. Rach, J. Budde, N. Möhle, M. Aufderheide

  • December 5, 2013

    Chemico-Biological Interactions 2013; 206:479-490

    “Use of the Cultex® Radial Flow System as an in vitro exposure method to assess acute pulmonary toxicity of fine dusts and nanoparticles with special focus on the intra- and inter-laboratory reproducibility”

    D. Steinritz, N. Möhle, C. Pohl, M. Papritz, B. Stenger, A. Schmidt, C. J. Kirkpatrick, H. Thiermann, R. Vogel, S. Hoffmann, M. Aufderheide

  • November 1, 2013

    Experimental and Toxicologic Pathology 2013; 65:1183–1193

    “A review of in vitro cigarette smoke exposure systems”

    D. Thorne, J. Adamson

  • July 1, 2013

    Experimental and Toxicologic Pathology 2013; 65:683-688

    “Detection of the cytotoxicity of water-insoluble fraction of cigarette smoke by direct exposure to cultured cells at an air-liquid interface”

    H. Nara, Y. Fukano, T. Nishino, M. Aufderheide


Radial Flow System for cell-based exposure


CULTEX® Company Brochure