Cytotoxicity Testing in Biomedicine and Ecotoxicology

Experimental studies on living human and animal cells, using advanced biological methods and cell-based assays like cytotoxicity tests, drive progress in both fundamental and applied biomedical research. By cultivating cells from different organs and tissues in the lab, researchers can conduct high-throughput experiments on living models - opening the door to innovative breakthroughs, all without the need for animal testing.

Fraunhofer EMFT offers development, adjustment and optimization of cell-based sensors or assays for 2D or 3D tissue models. The team in Regensburg provides consultancy services for assay design, suitable detection principles, material selection, functionalisation and integration into individual testing environments, and data analysis. The team also conducts feasibility studies for special assay formats and technologies. A wide range of label-free and molecular assays, as well as various combinations, have been developed and can be accurately deployed to address specific scientific issues in biomedicine, biotechnology and ecology.

Assessment of Biocompatibility for Medical Devices and Active Substances

Modern medical devices and pharmaceutical active substances must meet the highest standards of biological compatibility. To ensure that materials do not have harmful effects on human cells and tissues, various cytotoxicity tests are employed. These methods enable reliable laboratory assessment of biocompatibility and form the basis for the approval and further development of new products. Tests that provide time-resolved information are particularly significant, as they offer a deeper analysis of cellular reactions in addition to traditional endpoint assays.

A key component of these cytotoxicity tests is the contact test and the extract test, which illuminate different aspects of the interaction between materials and cells.

In the contact test, the sample is placed directly onto a cell culture. After an incubation period - typically lasting between 24 and 96 hours - the cells are examined to assess their response to direct contact with the material. If the cells show normal growth and high vitality, the sample is considered cytocompatible and thus biocompatible. A lack of cell growth or cell death indicates a cytotoxic effect of the sample.

Advantages

• Demonstrates the direct interaction between the material and cells under physical contact
• Suitable for materials intended as cell carriers or contact surfaces
• Enables evaluation of toxic effects before product application

This method is particularly suitable for testing materials that will later come into direct contact with body tissue, such as implants, wound dressings, or contact lenses. Microscopic analysis also allows for localized examination of different areas within a material or at the interfaces between two materials.

In contrast, the extract test examines whether a material releases harmful substances during use that could be toxic to cells. For this purpose, the sample is first placed in an extraction medium, allowing any soluble components to leach out of the material. The resulting extract is then applied to a cell culture. Using cell viability tests (e.g., metabolic assays), it is assessed whether the extracted substances have a cytotoxic effect.

Advantages

• Demonstrates whether materials may release harmful substances under real-use conditions
• Particularly relevant for materials that remain in the body for longer periods or come into contact with bodily fluids
• Suitable for a wide range of materials, regardless of their structure or form

This method is commonly used to screen medical devices, materials, and environmental samples for potentially releasable toxic substances.

Looking to verify the biocompatibility of your products through cytotoxicity testing?
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