Quantitative biocompatibility evaluation of nickel-free high-nitrogen stainless steel in vitro/in vivo.
Bottom Line: Endothelialization was greater with HNS than with commercial stainless steel (SUS316L).These differences may be related to the amounts of nickel ion eluted from the stents, as HNS did not elute nickel ion.These data suggest that HNS may be useful as a material for coronary artery stents.
Affiliation: Biomaterials Unit, Nano-Life Field, International Center for Materials Nanoarchitectonics (MANA) National Institute for Materials Science (NIMS), Tsukuba, Ibaraki, Japan.Show MeSH
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Mentions: After culture for 1 day, there were no significant differences in the number of HUVECs when comparing HNS and SUS316L. This means that the adhesiveness of HUVECs was similar regardless of the types of metal. However, the number of HUVECs after culture for 3 or 7 days was significantly higher on HNS than on SUS316L. To investigate the different proliferation behavior of HUVECs on HNS and SUS316L, we assessed Ni ion elution from these metals. Figure 3 shows the amount of Ni ions released from HNS or SUS316L disks after immersion in PBS for various periods. A total of 37.2 ± 7.7 μg/g/well of Ni ion was eluted from SUS316L after 1 day. The amount of Ni ion eluted from SUS316L gradually increased with time and reached 88.2 ± 19.7 μg/g/well after incubation for 7 days. In contrast, the amount of Ni ions eluted from HNS was below the detection limit (limit of detection: 1.2 ppb)31 even after immersion in PBS for 7 days. European regulations limit the amount of Ni ion that can be released from approved Ni-containing products that contact the skin to ≤0.5 μg/cm2/wk.16 In Japan, the use of coronary artery stents made of SUS316L is contraindicated in patients with Ni allergies.17 Thus, HNS may be more useful than SUS316L on the basis of Ni ion elution.
Affiliation: Biomaterials Unit, Nano-Life Field, International Center for Materials Nanoarchitectonics (MANA) National Institute for Materials Science (NIMS), Tsukuba, Ibaraki, Japan.