Nanostructural control of transparent hydroxyapatite nanoparticle films using a citric acid coordination technique

Zizhen Liu, Takuya Kataoka, Sadaki Samitsu, Daisuke Kawagoe, Motohiro Tagaya

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)


Hydroxyapatite (HA), as the main mineral component in hard tissues, has good biocompatibility. In particular, HA films are widely used as bioactive coatings for artificial bones and dental implants in biomedical fields. However, it is currently difficult to prepare a nanostructure-controlled HA film by a wet process for further applications. Herein, we report the synthesis of HA nanoparticles coordinated by citric acid (Cit/HA) based on the interactions between carboxylate and calcium ions to control the sizes and shapes of the hybrid nanoparticles, to improve their dispersibility in water and to eventually form uniform transparent films with nanospaces, and investigated the film formation mechanism. As compared with the well-known rod-like HA nanoparticles (size: 48 × 15 nm2), we successfully synthesized spherical and negatively charged Cit/HA nanoparticles (size: 25 × 23 nm2) to achieve highly transparent Cit/HA films using the spin-coating technique. The Cit/HA films had uniform and crack-free appearance. About the nanostructures, we found that the Cit/HA film surfaces had meso-scaled nanospaces with a diameter of 4.2 nm based on the regular arrangement of spherical nanoparticles, instead of the HA film with a nanospace diameter of 24.5 nm formed by non-uniform accumulation. Therefore, we successfully achieved the control of the nanospace sizes of the films with the nanoparticle arrangement and realized transparent nanoparticle film formation in a very simple way, which will provide more convenient bioceramic films for biomedical applications. This journal is

Original languageEnglish
Pages (from-to)396-405
Number of pages10
JournalJournal of Materials Chemistry B
Issue number3
Publication statusPublished - Jan 21 2022
Externally publishedYes

ASJC Scopus subject areas

  • General Chemistry
  • Biomedical Engineering
  • General Materials Science


Dive into the research topics of 'Nanostructural control of transparent hydroxyapatite nanoparticle films using a citric acid coordination technique'. Together they form a unique fingerprint.

Cite this