Electrochemical hydroxyapatite coatings on nitinol stents for the reduction of metal ions elution

Daisuke Kondo, Tomohiko Yoshioka, Toshiyuki Ikoma, Kensuke Takamatsu, Kunihiro Ohta, Junzo Tanaka

Research output: Contribution to journalConference articlepeer-review

1 Citation (Scopus)


Nitinol was coated with biocompatible calcium phosphate materials by pulsed electrolytic deposition (ELD) to reduce toxic metal-ions elution. The pulse ELD for the stents was carried out with changing the currentoff-periods (toff) of the pulse wave. The pulse ELD suppressed the generation of H2 gas due to the electrolysis of water on a calcium phosphate layer and improved the adhesiveness of the coating layer on nitinol compared with a conventional DC-ELD. The coating layers were identified to be octacalcium phosphate (OCP) at lower toff, while they were transformed to dicalcium phosphate anhydraous (DCPA) with an increase of toff. The layers of OCP or DCPA on the nitinol surface were subjected to a NaOH treatment at 60°C for 3days to transform them into hydroxyapatite (HAp). From results of a metal-ions elution test, the deposited calcium phosphates suppressed nickel ions elution at one quarter compared with the bare nitinol stent. These results indicate that the pulse ELD of biocompatible calcium phosphate materials on the nitinol stent was one of the best techniques to create firmly attached coating on it and reduce toxic nickel ions elution.

Original languageEnglish
JournalMaterials Research Society Symposium Proceedings
Publication statusPublished - 2014
Externally publishedYes
Event2013 MRS Fall Meeting - Boston, MA, United States
Duration: Dec 1 2013Dec 6 2013


  • biomaterial
  • coating
  • electrodeposition

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering


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