High-strength ceramics as innovative candidates for cardiovascular implants

Abstract

Cytocompatibility and hemocompatibility are essential features for tissue- and blood-contacting implants such as artificial heart valves, vascular grafts and stents. Platelet activation as the main trigger of thrombosis results in implant failures. The purpose of this study results from the demands on anti-coagulant and non-corrosive innovative biomaterials for cardiovascular implants. Therefore, hemocompatibility and cytocompatibility of various high-strength ceramics, such as alumina, zirconia, silicon nitride and silicon carbide, were examined to identify the most appropriate ceramic for cardiovascular implants. In addition to the material species, different crystallographic structures (single- and poly-crystalline) and surface terminations (Si and C faces) of silicon carbide were used in order to reveal the interactions between blood and material surface. Three cell types, i.e. human umbilical vein endothelial cells, mesenchymal stem cells and blood cells, were cultured on the substrates and their interactions with material surfaces were analyzed. Cytotoxicity of the materials was tested by live/dead staining. Hemocompatibility in terms of platelet and white blood cell activation was examined via scanning electron microscopy and indirect ELISA. To mimic physiological conditions in vitro, the hemocompatibility of the materials was additionally analyzed in a bioreactor under dynamic flow conditions in comparison to static incubation. All ceramics were found to be cytocompatible for mesenchymal stem cells, human umbilical vein endothelial cells and blood cells. The highest number of resting, non-activated platelets was observed on the monocrystalline silicon carbide demonstrating that this material triggers the platelet activation less compared to the other materials. It is found to be the most appropriate ceramic for blood-contacting implants in terms of cell adhesion, cell viability, and hemocompatibility.

Toward Innovative Hemocompatible Surfaces: Crystallographic Plane Impact on Platelet Activation

“…Viability values indicated that all single crystalline samples are cytocompatible for HUVECs and PBMCs. These results were predicted due to the nontoxic characteristics of polycrystalline Al 2 O 3 and SiC ceramics observed in our previous study, as well as earlier reports. − Toxicity of the Triton-X100-treated control surface was already addressed in many studies, which caused total cell destruction for both HUVECs and PBMCs. − TX100 causes the disruption of hydrogen bonds within the cell’s lipid bilayer. Thus, the lipid membrane loses its compactness and integrity, which resulted in cell death .…”

“…As a full activation control (positive control), platelet solution was transferred to an empty 24-well plate. Further steps of the ELISA were described previously by Parlak et al…”

Unveiling the main factors triggering the coagulation at the SiC‐blood interface

“…Subsequently, the intensity of UV‐marker was measured using Tecan microplate reader at 450 nm. Detailed steps of the ELISA were described previously 26 …”

Incorporation of Controlled Release Systems Improves the Functionality of Biodegradable 3D Printed Cardiovascular Implants

“…ZnO nanoparticles, a FDA recognized biocompatible material, generates NO continuously from endogenous NO donors in blood circulation . It has been shown that some classes of ceramics and glasses, especially monocrystalline silicon carbide, could potentially act as hemocompatible materials for the development of blood-contacting surfaces …”

“…112 It has been shown that some classes of ceramics and glasses, especially monocrystalline silicon carbide, could potentially act as hemocompatible materials for the development of bloodcontacting surfaces. 113 Heparin is one of the anticoagulant agents that has been coated on the surface of 3D printed PLA vascular stents. The in vitro and in vivo findings revealed an inhibition of neointimal hyperplasia, thrombosis, and atherosclerosis (Figure 3d).…”