Fluorescent Hemolysis Detection (FHD): Vaidation of the in-vitro test method

• Applicant: Professor Dr.-Ing. Ulrich Steinseifer
• Subject Area: Medical Physics, Biomedical Technology
• Term: from 2016 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 321130633

Cardiac assist devices (e.g. blood pumps or artificial heart valves) are frequently used for the treatment of cardiovascular diseases as an alternative for transplantations. Despite the improvement of the aforementioned systems, severe complications like hemolysis (red blood cell destruction), thrombosis or bleeding events still occur frequently and therefore bear high risks for patients and cause high therapy and follow-up costs at the same time.Hemolysis describes red blood cells’ (RBCs) membrane destruction, which leads to the loss of hemoglobin. Hemoglobin is responsible for the oxygen transport and is thus crucial for the oxygen supply of the whole body. Currently, neither in-silico nor in-vitro techniques allow for evaluating the hemolysis origin in cardiac assist devices. Hence, major hemolysis hotspots are detected late during device development or in the worst case during patient treatment. A new approach for overcoming the deficit of spatially resolved hemolysis detection was offered by the Fluorescent Hemolysis Detection (FHD) method.The FHD method is based on ghostcells (GCs), which are RBCs lacking hemoglobin due to controlled lyses of the cells. During lyses, GCs are loaded with a marker and added into an artificial plasma, containing an indicator sensitive to the marker. In case of hemolysis, the marker from the GCs’ interior is released into the artificial plasma where it reacts with the fluorescence indicator, highlighting the origin of hemolysis.During the previous DFG-funded project, main aspects of the FHD method were addressed: large volume production of loaded GCs, rheology adaption of GCs to RBCs’ rheology, deformation ability of loaded GCs compared with RBCs, and membrane impermeability of GCs with respect to the marker. It was shown that loaded GCs properties are similar to RBCs in terms of rheology and impermeability.Within the follow-up application, the FHD method will be validated as a spatially and temporally resolved method for the evaluation of hemolysis in blood conducting devices. Up to now, only chemical hemolysis was detected by the FHD method. At the end of this project, mechanical hemolysis will be detectable in a centrifugal blood pump, combined with PIV measurements and spatially resolved hemolysis detection. Therefore, the impact of PIV particles as well as the resolution limits with regard to time and place will be evaluated. Additionally, the GC hemolysis threshold will be compared to RBCs to establish a quantitative hemolysis analysis. The results of this work will allow for a-priori evaluation of medical devices in terms of hemolysis, as results will not only improve in-vitro test methods but also influence CFD simulations. Simulation models can incorporate new insights into medical devices hemolysis and will improve their hemolysis prediction significantly. In the long run, results of this method will improve blood conducting devices and therewith patient care and safety.

• DFG Programme: Research Grants