Study of the biological activity of laser powder bed fusion Zn-1Mg and Zn-1Mg-1Ag (wt.%) intended for cardiovascular stenting applications

Abstract

Nowadays, biodegradable Zn is gaining popularity across diverse applications, including orthopedic scaffolds, wound closure devices, and cardiovascular stents, due to its moderate corrosion rate and biological relevance. However, studies on cell viability and inflammatory responses in human coronary artery endothelial cells (HCAEC), erythrocyte compatibility, and platelet adhesion activity are imperative for evaluating Zn alloys used in laser powder bed fusion (LPBF) manufactured cardiovascular stents. In this study, Zn-1Mg and Zn-1Mg-1Ag (wt.%) cast rods were powdered by ultrasonic atomization in an Ar atmosphere using a rePowder device (AMAZEMET, Poland). Afterward, LPBF printing was performed using an AconityMIDI (AMAZEMET, Poland) with the following parameters: 75 W of laser power, 420 mm/s of scanning speed, 30 µm of layer thickness, 70 µm of hatch distance, and 75 µm of laser beam size. To assess cytocompatibility, HCAEC supplemented with 5% fetal bovine serum (FBS) were used for the indirect method of testing at a concentration of 10%; additionally, the release of pro-inflammatory cytokine (IL-6) and chemokine (MCP1) was analyzed via ELISA test. In addition, hemocompatibility was studied using blood from a healthy volunteer. The platelet-containing plasma fraction was used for platelet adhesion observations. Cytocompatibility testing in HCAEC provides insight into how specialized cells respond to Zn alloys, including proinflammatory responses indicating viability at 10% extract concentration, especially on Zn-1Mg-1Ag. However, better results in hemolysis and platelet adhesion were observed for Zn-1Mg. The results suggest that Ag strongly influences the biological response, resulting in higher cellular metabolic activity compared to Zn-1Mg, while slightly compromising blood compatibility.