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Important issues in the cytotoxicity screening of nano-sized materials

Abstract Due to their extraordinary properties nano-sized materials (NMs) are increasingly used in industrial, pharmaceutical and medical applications. An even broader use is currently limited by concern about their potential adverse effect on health. Screening for toxic effects of all engineered NMs therefore, is needed to demonstrate biocompatibility. The identification of adverse cellular effects is one of the first steps in the toxicological assessment of drug compounds before they get to the market. A panel of cytotoxicity screening assays is available and can be used also for the assessment of NMs. The use of these established and validated assays for the testing of NMs, however, is complicated by the fact that NMs may interfere by color, chemical reactivity and light scattering leading to false positive or false negative results. The paper illustrates the principles of conventional cytotoxicity screening assays and discusses their suitability for the assessment of NMs. Adequate controls to identify interference and alternatives, if interference with the used assay is seen, are suggested.