Hemocompatibility (in vitro)
Membranes for medical use are mainly produced as hollow-fibers as part of class IIb medical devices studies. Dialysis und oxygenation membranes in extracorporal circuits are in contact with heparinised patient blood. Hemocompatibility is a major goal and a prerequisite for approval of devices used in extracorporeal circuits such as hemodialyzers and blood oxygenators. Therefore, during development and finally release of products for clinical tests it is mandatory to perform careful and reliable hemocompatibility assessment as close as possible to the clinical application e.g. using the same device (lot) as during the clinical study.
We perform our pre-clinical tests in an extracorporeal circuit using clinical sized modules and freshly donated, heparinized human blood. In our studies we recommend to compare hemocompatibility parameters of a newly developed membrane or device with products which are already approved and in clinical use. Thus, the results can more easily be extrapolated to the clinical situation.
In our set-ups we can compare up to six dialyzers and four oxygenators in parallel to assess the hemocompatibility according to ISO 10993-4 of
- Clinical size medical devices (ca. 0.2-2.5 m²)
- Miniaturised (down-scaled) devices (ca. 250 cm²)
- Polymer films or flat sheet membranes (ca. 10-25 cm²)
- Powders, suspensions etc.
Hemocompatibility parameters routinely measured in our laboratory include:
- C5a (fragment of complement factor C5) as a read out of complement activation (ELISA)
- TAT (Thrombin/Antithrombin III Komplex) indicating activation of the clotting system (ELISA)
- Heparin consumption (anti factor Xa, chromogenic substrate assay)
- Platelet count as parameter of platelet activation (cell counter)
- Several methods for the measurement of redness caused by residual blood in the dialyser (image analysis, chromameter).
- CR3/CD62L (expression of adhesion receptors) to determine activation of neutrophils (flow-cytometry)
- Interleukin-1ß (cytokine release) as parameter of monocyte activation (ELISA)
In principle, analysis of any biochemical parameter is possible (see our directory of services). Please contact us if you do not find the parameter in question in our directory of services since we can only list parameters which are within the scope of our accreditation. However, it is our speciality and we are very interested to establish new parameters and methods within the scope of our biomedical expertise. (Research and development)