Ensuring the safety of complex bio-based materials: The key role of in vitro bioassays

The transition to a more sustainable economy has driven the development of bio-based materials, obtained from renewable sources such as starches, agricultural waste, plant extracts or by-products of biotechnological processes. These materials are proposed as ecological alternatives to conventional fossil-based materials, with applications in sectors such as packaging, cosmetics, construction or the automotive industry.

However, their natural nature and the techniques used for their transformation (extraction, functionalization, polymerization, fermentation, etc.) often generate chemically complex mixtures. These formulations, known as UVCB (Substances of Unknown or Variable Composition, Complex Reaction Products or Biological Materials), may contain ill-defined compounds, by-products of processing, precursor residues or functional additives, the complete characterization of which is not always possible. In addition, due to the inherent variability of raw materials and process conditions, the final composition of the material can change significantly between batches, making it even more difficult to evaluate.

This level of complexity poses difficulties in ensuring toxicological safety, especially in sensitive applications such as consumer products, medical devices, cosmetics or food contact materials. In many cases, it is not feasible to rely solely on chemical analysis, as not all the compounds present or their potential toxicity are known.

In vitro bioassays: an effective tool for assessing bio-based materials

Faced with this challenge, in vitro bioassays are presented as an effective and complementary tool. They make it possible to detect real biological effects – such as genotoxicity, cytotoxicity, oxidative stress or hormonal activity – even in extracts whose chemical composition is not fully identified. In addition, they are fast, reproducible methods aligned with the 3Rs principle, making them a solid alternative to traditional in vivo assays .

At AIMPLAS we apply a battery of bioassays validated by the OECD, adapted to the type of material and its final application. These include:

• the Ames test (OECD 471) for mutagenicity,
• the micronucleus assay (OECD 487) to assess chromosomal damage,
• the comet assay (OECD 489) to detect DNA breaks,
• and complementary cell assays to study cytotoxicity or oxidative stress.

Safe and Sustainable by Design (SSbD) approach in materials development

In addition, this strategy is articulated within a broader approach based on the principles of Safe and Sustainable by Design (SSbD). From the early stages of material development, we combine bioassays with untargeted chemical analysis (NTA) techniques, allowing us to identify bioactive fractions and prioritize risks, even when full substance identification is not possible.

Risk-proportionate toxicological assessment of food contact materials

As proposed by EFSA, the toxicological assessment of complex materials such as bio-based materials should be adapted to the expected level of exposure, especially when it comes to food contact materials. At AIMPLAS we follow this step-by-step model, which considers the amount of substances that migrate from the packaging to the food. When migration is minimal, additional testing may not be necessary. However, if certain thresholds are exceeded (e.g. 0.05 mg/kg), it is advisable to apply in vitro bioassays to check the absence of genotoxic or cytotoxic effects. This approach allows us to evaluate materials in proportion to the real risk, offering safe, personalized and efficient solutions.

Thus, in vitro bioassays not only offer a solid scientific basis to ensure the safety of new bio-based materials, but also allow innovation, sustainability and regulatory responsibility to be aligned. This integration facilitates industrial acceptance, anticipates potential legal barriers, and guides safer and more sustainable design decisions.