Methodology
Problems and challenges in the development and validation of human cell-based assays to determine nanoparticle-induced immunomodulatory effects
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* Corresponding author: Gertie J Oostingh geja.oostingh@sbg.ac.at
1 Department of Molecular Biology, University of Salzburg, 5020 Salzburg, Austria
2 Institut Català de Nanotecnologia (ICN), 08193 Bellaterra, Spain
3 Laboratory of Innate Immunity and Cytokines, Institute of Biomedical Technologies, National Research Council (CNR), 56124 Pisa, Italy
4 European Commission, Joint Research Centre (JRC), Institute for Health and Consumer Protection, Nanobiosciences Unit, 21027 Ispra, VA, Italy
5 Fraunhofer Institute for Biomedical Engineering, Department of Biohybrid Systems, 66386 St. Ingbert, Germany
6 Centre for Advanced R&D on Alternative Methods (CARDAM), Flemish Institute for Technological Research (VITO NV), 2400 Mol, Belgium
7 Institució Catalana de Recerca i Estudis Avançats (ICREA), 08010 Barcelona, Spain
Particle and Fibre Toxicology 2011, 8:8 doi:10.1186/1743-8977-8-8
Published: 9 February 2011Abstract
Background
With the increasing use of nanomaterials, the need for methods and assays to examine their immunosafety is becoming urgent, in particular for nanomaterials that are deliberately administered to human subjects (as in the case of nanomedicines). To obtain reliable results, standardised in vitro immunotoxicological tests should be used to determine the effects of engineered nanoparticles on human immune responses. However, before assays can be standardised, it is important that suitable methods are established and validated.
Results
In a collaborative work between European laboratories, existing immunological and toxicological in vitro assays were tested and compared for their suitability to test effects of nanoparticles on immune responses. The prototypical nanoparticles used were metal (oxide) particles, either custom-generated by wet synthesis or commercially available as powders. Several problems and challenges were encountered during assay validation, ranging from particle agglomeration in biological media and optical interference with assay systems, to chemical immunotoxicity of solvents and contamination with endotoxin.
Conclusion
The problems that were encountered in the immunological assay systems used in this study, such as chemical or endotoxin contamination and optical interference caused by the dense material, significantly affected the data obtained. These problems have to be solved to enable the development of reliable assays for the assessment of nano-immunosafety.