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In vitro bioassays

The use of bioassays makes it possible to assess the safety and efficacy of a wide range of materials and substances.

Bioassays or in vitro assays are specialized techniques using organisms, which may include cell cultures, bacteria, fungi, insects, plants and arthropods, under controlled laboratory conditions.

What are in vitro bioassays used for?

They are used in several different areas of science to understand the reactions of an organism to the presence of one or more known or unknown substances. Reactions may include different negative effects such as cytotoxicity and genotoxicity, as well as positive effects such as protection against oxidizing agents. The use of bioassays therefore makes it possible to assess the safety and efficacy of a wide range of materials and substances, thus reducing the use of animal testing, which should only be used when no alternative methods exist, in keeping with the three Rs principle (replacement, reduction and refinement), as set out in EU Directive 2010/63.

What are the advantages of in vitro bioassays?

They enable effects to be assessed without the need to identify or quantify the substance.

  • They make it possible to study the effects of mixtures to assess possible synergistic effects.
  • They make it possible to assess the effects of substances present at very low levels.
  • They reduce animal experimentation.

Types of in vitro bioassays

Depending on the effect to be evaluated, there are different types of in vitro bioassays to study the safety and/or efficacy of substances and materials. At AIMPLAS, we have biosafety laboratories with all the equipment required to carry out the following studies:

Evaluation of safety

  • Cell viability or cytotoxicity using colorimetric, fluorometric and bioluminescent techniques to assess cell damage and/or survival. The methods include:
    • MTT assay
    • Neutral Red
    • Alamar Blue
  • Genotoxicity tests to assess DNA damage at different levels:
    • Ames test (OECD TG 481) or bacterial reversion test to evaluate point mutations.
    • Micronucleus test (OECD TG 487) for evaluation of numerical and structural chromosomal mutations.
    • Comet assay (OECD TG 489) to measure DNA strand breaks, considered an indicator for detecting premutagenic lesions.

Evaluation of efficacy

  • Evaluation of the antioxidant potential or protective effect against oxidative stress of a substance, ingredient or material.
  • Studies of intestinal absorption.
  • Evaluation of antimicrobial activity.

Areas of application of in vitro bioassays

Food and cosmetic packaging

In the food packaging sector, the risk assessment of non-intentionally added substances (NIAS) that may migrate from packaging to food, required by legislation (Regulation 10/2011), is a major resource-intensive challenge. This is mainly because risk assessment requires prior chromatographic identification of all substances detected in a chromatographic screening whose concentration is above the threshold of toxicological concern defined for genotoxic substances and, in many cases, this is not technically possible.

In vitro bioassays and genotoxicity studies in particular help rule out genotoxic effects of NIAS migrated from packaging, thus making it possible to significantly increase the threshold of toxicological concern. This greatly simplifies the risk assessment of NIAS, given that the number of substances to be identified after chromatographic screening is much lower.

Given that the cosmetics industry does not have specific legislation regulating packaging, but does require a risk assessment in accordance with Regulation 1223/2009 on cosmetic products, this industry is governed by the legislation applicable to materials intended for food contact (Regulation 10/2011) when verifying the suitability of cosmetic packaging. Given that everything mentioned about NIAS in food packaging is applicable to cosmetic packaging, in vitro bioassays are also a very useful tool for validating the safety of cosmetic packaging.


In vitro bioassays can also be used as a tool for assessment of risks due to the presence of microplastics in food, either as a consequence of contact with plastic packaging or due to contamination at specific points in the food chain. Studies to assess cytotoxic, genotoxic and oxidative stress effects are therefore common. However, further studies are also necessary to assess the dissolution/degradation capacity of microplastics under lysosomal and gastrointestinal conditions, as well as their cellular uptake capacity.

Medical devices

In vitro bioassays are an indispensable tool in the safety assessment of medical devices. AIMPLAS can perform the in vitro bioassays required by Regulation (EU) 2017/745 on medical devices for manufacturers of these devices, the aim of which is to guarantee their biocompatibility with the human body. It is therefore necessary to design a battery of minimum tests depending on the product category, type of contact and duration.

Functional ingredients

In addition to safety, in vitro bioassays are also used to assess the efficacy of substances, mixtures and materials. In the food industry, for an ingredient to be considered functional, studies must be carried out to demonstrate the ingredient’s beneficial properties. Some of the in vitro bioassays carried out at AIMPLAS include evaluation of the protective effect against oxidative stress (antioxidant potential) and studies on intestinal absorption.

In the cosmetics and building materials industries, the use of antimicrobial additives is also very common to prevent contamination by microorganisms in cosmetic products and surface materials such as countertops, floors and coatings. The effectiveness of these antibacterial and antifungal additives must be demonstrated by means of antimicrobial efficacy studies. AIMPLAS can carry out these studies to ensure the effectiveness of these materials.


What is a bioassay and what is it for?

Bioassays are used to evaluate the safety or efficacy of a compound through the response of a living organism.

What does biocompatibility mean?

Biocompatibility refers to the ability of a biomaterial to perform a function according to a treatment without causing any adverse effects that could compromise cell viability and, as a result, the patient’s health.