Tissue engineering combines principles from biology, engineering, and materials science to develop biological tissues. These can be used to replace or regenerate damaged or missing tissues in the body, such as skin, cartilage, or cardiac tissue. This approach also opens new possibilities in wound healing (through the use of bioactive materials), transplantation medicine (reducing dependence on donor organs), and drug development (using artificial tissues for pharmaceutical testing).
At Fraunhofer IMWS, our focus is on advancing cell-based test systems, including the development of innovative methods for determining biological parameters.
Cell-Based Test Systems for the Determination of Biological Parameters
To analyze biological parameters of samples and substances, we employ a range of cell-based testing systems, including:
- Bioactivity, cytotoxicity, and immunogenicity testing
- Testing the cell adhesion, cell integration, and cell growth properties of materials or material surfaces. Detection of DNA and microbial residues
Cytotoxicity Testing of Materials Using In-Vitro Model Systems
We offer three well-established methodological approaches:
- Conventional cell cultures
- Reconstructed three-dimensional skin models
- Vascular models
These approaches enable both qualitative and quantitative assessment of cytotoxicity:
- Qualitative methods rely on microscopic analysis of morphological changes in cells (e.g., shrinkage, detachment, or membrane damage).
- Quantitative methods use colorimetric, fluorometric, or luminescence-based assays (e.g., MTT, resazurin assay, XTT, LDH, or ATP assays), typically evaluated using photometric techniques.
Depending on the research question and model complexity (2D vs. 3D), different cell types are used, such as fibroblasts, keratinocytes, or endothelial cells. In 3D skin and vascular models, particular emphasis is placed on achieving physiologically relevant cell architecture and barrier function.
Cytotoxicity testing can be performed using three different methods:
1. Extract testing (elution method):
The test material is transferred into an extraction medium, which is then applied to the cell or tissue model. This method is particularly suitable for soluble or leachable substances and is compatible with 3D models.
2. Direct contact:
The test material is applied directly to the cell culture or tissue model. This allows evaluation of mechanical or physical effects but is only suitable to a limited extent for sensitive 3D structures.
3. Indirect contact (e.g., agar overlay method):
A physical barrier (e.g., an agarose layer) separates the material from the cells while allowing the diffusion of substances. This method is particularly suitable for materials with potentially irritating surface properties.
Fraunhofer Institute for Microstructure of Materials and Systems IMWS