<p>New developments are needed in aortic replacement, with current hybrid solutions suffering from insufficient and rigid stent diameters, thus hindering minimization of false lumen in aortic dissection. Laser powder bed fusion (L-PBF) is an attractive method to generate a new-generation aortic stent. This study investigates the effects of 316 L stainless steel samples manufactured using the L-PBF process on the activity of fibroblasts, red blood cells, leukocytes and platelets on the modified surfaces. Cytotoxicity and hemocompatibility were analyzed under static culture conditions using immunofluorescence as well as scanning electron microscopic (SEM) techniques. Surfaces of additively manufactured samples were etched, electropolished, heat‑treated, and mechanically expanded to optimize the material’s mechanical performance. Alone heat treatment increased the ultimate tensile strength from 585 ± 5 MPa to 695 ± 6 MPa. The additive manufactured and post-processed stents were non-cytotoxic (viability, &gt; 70%, independent of the manufacturing status), non-hemolytic (hemolysis rate, &lt; 1%), and were covered with only a few neutrophils (median (IQR), 25 (12-48) per mm<sup>2</sup>) and platelets (cellular coverage, 0.5 - 10%). Material-induced formation of neutrophil extracellular traps (NETs) was low and not quantifiable. More than 80% of adherent platelets presented an activated conformation and increased expression of CD62P. In contrast, neither circulating leukocytes nor platelets in the supernatant showed any material-induced stimulation as detected via flow cytometry. The results described herein are encouraging and suggest that additive manufactured metallic stents are bio- and hemocompatible and an adequate candidate material for personalized stent production in a very short time.</p><p></p>

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Hemocompatibility and cytotoxicity evaluation of additively manufactured and surface-treated 316 L stainless steel aortic stents using laser powder bed fusion (L-PBF)

  • Philipp Lulla,
  • Lukas Esper,
  • Ulf Noster,
  • Thomas Schratzenstaller,
  • Christof Schmid,
  • Karla Lehle

摘要

New developments are needed in aortic replacement, with current hybrid solutions suffering from insufficient and rigid stent diameters, thus hindering minimization of false lumen in aortic dissection. Laser powder bed fusion (L-PBF) is an attractive method to generate a new-generation aortic stent. This study investigates the effects of 316 L stainless steel samples manufactured using the L-PBF process on the activity of fibroblasts, red blood cells, leukocytes and platelets on the modified surfaces. Cytotoxicity and hemocompatibility were analyzed under static culture conditions using immunofluorescence as well as scanning electron microscopic (SEM) techniques. Surfaces of additively manufactured samples were etched, electropolished, heat‑treated, and mechanically expanded to optimize the material’s mechanical performance. Alone heat treatment increased the ultimate tensile strength from 585 ± 5 MPa to 695 ± 6 MPa. The additive manufactured and post-processed stents were non-cytotoxic (viability, > 70%, independent of the manufacturing status), non-hemolytic (hemolysis rate, < 1%), and were covered with only a few neutrophils (median (IQR), 25 (12-48) per mm2) and platelets (cellular coverage, 0.5 - 10%). Material-induced formation of neutrophil extracellular traps (NETs) was low and not quantifiable. More than 80% of adherent platelets presented an activated conformation and increased expression of CD62P. In contrast, neither circulating leukocytes nor platelets in the supernatant showed any material-induced stimulation as detected via flow cytometry. The results described herein are encouraging and suggest that additive manufactured metallic stents are bio- and hemocompatible and an adequate candidate material for personalized stent production in a very short time.