Demonstrated applicability to “difficult-to-test” samples.

The challenges

In the context of skin sensitization testing, certain groups of chemicals are considered “difficult-to-test” using conventional cell-based methods. Examples of commonly recognised “difficult-to-test” samples include:

  • Pre- and pro- haptens

    Pre- and pro-haptens need to be activated to become skin sensitizers. The metabolic activation process, however, is not always supported by in vitro tests.

  • Low water-soluble substances

    Hydrophobic test items are often difficult to test in an aqueous test system due to solubility issues.

  • Surfactants

    Many surfactants have cell membrane-damaging properties and tend to generate false-positive results.

  • Complex mixtures

    Botanical extracts, essential oils or UVCBs are typical examples of complex mixtures. Many of them have solubility issues in aqueous test systems.

The GARD® solution

GARDskin has demonstrated broad applicability for various types of difficult-to-test samples. The scientific data is summerized in the OECD TG 442E.*

Supporting metabolic activation

GARDskin utilizes a dendritic-like cell line, expressing several metabolizing enzymes required for activation of pre/-pro haptens (e.g. ALDH, CYP, NAT-1).

A broad selection of solvents

The solubility for hydrophobic substances is further increased using an extended panel of non-polar solvents compatible with the test system.

Highly sensitive

GARDskin is highly sensitive, able to detect a minimum amount of substances dissolved in the cell medium.

Publications in collaboration with Lubrizol, Johnson Matthey and Corteva

Forreryd, A., Gradin, R., Humfrey, C., Sweet, L. and Johansson, H. (2022). Exploration of the GARD™ skin applicability domain: Indirectly acting haptens, hydrophobic substances and UVCBs. ALTEX.

Forreryd, A., Gradin, R., Rajapakse, N., Deag, E. and Johansson, H. (2022). The GARD™skin assay: Investigation of the applicability domain for metals. ALTEX.

Corvaro, M., Henriquez J., Settivari, R., Mattson, U.T., Forreryd, A., Gradin, R., Johansson, H. and Gehen, S. (2022). GARD™skin and GARD™potency: a proof-of-concept study to investigate the applicability domain for agrochemical formulations. Manuscript submitted.

  • Complex mixtures successfully tested at SenzaGen’s lab

    From natural extracts to UVCBs, and different types of finished formulations

  • What are your difficult-to-test samples?

    Over 500 samples have been successfully tested at SenzaGen’s lab, many of them are considered difficult-to-test samples

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