DescriptionAim: To evaluate the effect of various biomaterials used in ventricular assist devices (VADs) on leukocyte behaviour to identify the most biocompatible. The results will impact future VAD designs to reduce common complications such as thromboembolism and infection. Methods: Discs of biomaterials used in VAD designs - single-crystal sapphire (SAP), silicon nitride (SIN), zirconia toughened-alumina (ZTA) and titanium alloy (TI) - were suspended on polypropylene beads in petri dishes; beads only served as a negative control. Heparinised human peripheral blood was added to each dish and incubated at 37°C on a shaking plate. After 2h, the blood was removed and used for cell count analysis using the Cell-DYN Ruby haematology analyser; haemolysis using the Harboe assay (plasma-free haemoglobin, g/L); viability through flow cytometry using CyTRAK Orange™ and DRAQ7™; and whole blood cultures with 10 ng/mL LPS stimulation for 24hrs to yield supernatants for cytokine analysis using ELISA. Results: Preliminary data shown as fold change from negative control. Cell viability between the biomaterials (n=3) did not vary but a decrease in leukocyte numbers (n=6) was noted: 0.89±0.6 (SAP); 0.88±0.6 (SIN); 0.91±0.2 (TI); and 0.92±0.5 (ZTA). Haemolysis increased for every biomaterial (n=5): 1.41±0.25 (SAP); 2.12±0.66 (SIN); 1.52±0.84 (TI); and 1.39±0.64 (ZTA). Interleukin-8 (IL-8) concentration in LPS-stimulated samples varies by biomaterial (n=3): 0.90±0.54 (SAP); 1.53±1.08 (SIN); 1.24±0.23 (TI); and 1.15±0.29 (ZTA). Conclusions: The decrease in leukocyte numbers could be due to activation and adhesion of these cells, particularly monocytes and neutrophils, caused by the biomaterials and not simply cell death. Silicon nitride so far has shown higher haemolysis, a greater decrease in leukocyte count, and a higher concentration of IL-8 indicating poorer biocompatibility than the other biomaterials. Ongoing work includes flow cytometry for cell activation markers and microscopy for adhesion.
|Event title||European Society for Artificial Organs|
|Degree of Recognition||International|