Overview
ISO 19007:2018 - "Nanotechnologies - In vitro MTS assay for measuring the cytotoxic effect of nanoparticles" - specifies a harmonized method to evaluate the effect of nano-objects and their aggregates/agglomerates (NOAA) on cell viability using the MTS colorimetric assay. The standard defines assay design, performance requirements and control experiments to identify and manage variability. It is written for use with a 96‑well tissue culture plate and is primarily targeted to adherent mammalian cell systems (with optional adaptations for other formats).
Key topics and technical requirements
- Assay principle: MTS reagent is reduced by cellular enzymes to a formazan product; absorbance (peak ~490 nm) is proportional to viable cell metabolism under standard conditions.
- Test scope: Measurement of nanoparticle cytotoxicity for NOAA, including aggregates and agglomerates.
- Controls and performance criteria:
- Negative and positive control materials to establish baseline and expected cytotoxic response.
- Control experiments to detect nanoparticle interference with the colorimetric readout (e.g., optical or reagent interactions).
- Plate reader uniformity verification and precision pipetting requirements to reduce variability.
- Sample and plate preparation:
- Requirements for cell line maintenance, cell seeding, nanoparticle dosing plates, exposure procedures and MTS reagent exposure.
- Emphasis on characterizing nanoparticles in suspension and documenting preparation steps to ensure reproducibility.
- Data handling: Methods for measuring formazan absorbance, computing cell viability, and interpreting assay results with attention to assay‑specific artifacts.
- Annexes: Practical example protocols and interlaboratory study-derived procedures (e.g., A549 and RAW 264.7 examples) and a list of potential cell lines and alternative assays.
Practical applications
- Routine in vitro screening of nanoparticle cytotoxicity during research, product development and preclinical safety assessment.
- Interlaboratory harmonization and method validation for nanotoxicology studies.
- Regulatory and compliance testing where standardized, reproducible cell‑based cytotoxicity data are required.
- Quality control for nanomaterial manufacturing to detect biological activity early in the development pipeline.
Who should use ISO 19007:2018
- Nanotoxicologists, in vitro assay laboratories, contract research organizations (CROs)
- Academic researchers studying nanoparticle–cell interactions
- Product developers and safety assessors in nanomaterials, pharmaceuticals, cosmetics and advanced materials
- Regulatory bodies and standards professionals seeking reproducible cytotoxicity data
Related standards
- ISO/TS 80004-2 (Nanotechnologies - Vocabulary: nano-objects)
- ISO 10993-5 (Biological evaluation of medical devices - in vitro cytotoxicity)
- Other standardized cytotoxicity assays (MTT, XTT, LDH) are referenced for complementary testing.
Keywords: ISO 19007:2018, MTS assay, nanoparticles, nanotechnologies, cytotoxicity, in vitro, NOAA, 96‑well plate, cell viability, assay interference.
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