The Organization for Economic Cooperation and Development (OECD) recently released a crucial update of its safety testing framework for nanomaterials. The Adolphe Merkle Institute’s Co-Chair of BioNanomaterials, Prof. Alke Fink, contributed to the expert group developing these revised standards, ensuring they reflect how nanoparticles actually behave under realistic experimental conditions.

The OECD’s newly released guidance establishes how nanoparticles should be prepared, characterised, and dosed to ensure they’re safe as the technology expands into medicine, imaging, catalysis, advanced polymers, sensing, and other fields of use. For the framework’s authors, nanoparticle safety testing only works when sample preparation, physicochemical characterization, and dosimetry are treated as one integrated process. This is particularly important since nanoparticles can undergo changes at their surface, as well as in their dispersion state and stability, once they enter biological or physiological media containing proteins, salts, and other components.

“Reliable characterization in relevant media is central to nanosafety testing, especially in biological systems,” explains Fink, who was a member of the organization’s expert group. “Many commonly used biological assays were not originally developed for testing nanoparticles, particularly under realistic biological conditions.”

The OECD updated its guidance, as research over the past decade has shown that nanoparticles behave very differently from classical chemicals. And without harmonized protocols for preparation, characterization, and dosimetry, results for safety evaluation are often not comparable across laboratories, and biological effects cannot be reliably interpreted. For example, nanoparticles’ properties can change during an experiment, making their continuous characterization in the relevant media crucial.

“Preparation and dosimetry are essential, but without proper characterization, you cannot know what actually reaches the cells or in what amount,” adds Fink.

Fink specifically contributed her specialized expertise in nanoparticle characterization under realistic biological conditions. This includes colloidal stability, nanoparticle–protein interactions, and practical dispersion and dosimetry strategies. Her contribution supported the expert group’s work in ensuring that the recommendations reflect both current scientific understanding and workable laboratory practice.

Looking ahead, implementing the updated guidance will require continued attention to nanoparticle characterization under realistic exposure conditions. Because particle surface properties and dispersion state depend strongly on the surrounding medium, no single universal protocol can cover all materials and applications. Researchers will need interdisciplinary expertise and careful experimental design to ensure that preparation, characterization, and dosimetry remain aligned throughout a study. While this adds scientific complexity, the framework provides a common reference point that strengthens the transparency, reproducibility, and global comparability of nanosafety data.

Reference: Guidance on Sample Preparation and Dosimetry for Manufactured Nanomaterials, 2025 Edition