Bioactive bredigite coating with improved bonding strength, rapid apatite mineralization and excellent cytocompatibility

Our plain-English summary of Bioactive bredigite coating with improved bonding strength, rapid apatite mineralization and excellent cytocompatibility, by D. Yi, C. Wu, B. Ma, et al (Journal of Biomaterials Applications, 2014).

The study

• Authors: D. Yi, C. Wu, B. Ma, H. Ji, X. Zheng, J. Chang
• Journal: Journal of Biomaterials Applications
• Published: 2014;28(9):1343-53
• Cited by: 18 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Previous studies have shown that bredigite (Ca7MgSi4O16) bioceramics possessed excellent biocompatibility, apatite-mineralization ability and mechanical properties. In this paper, the bredigite coating on Ti-6Al-4 V substrate was prepared by plasma spraying technique. The main compositions of the coating were bredigite crystal phase with small parts of amorphous phases. The bonding strength of the coating to Ti-6Al-4 V substrate reached 49.8 MPa, which was significantly higher than that of hydroxyapatite coating and other silicate-based bioceramic coatings prepared by same method. After immersed in simulated body fluid for 2 days, a distinct apatite layer was deposited on the surface of bredigite coating, indicating that the prepared bredigite coating has excellent apatite-mineralization ability. The prepared bredigite coating supported the attachment and proliferation of rabbit bone marrow stem cells. The proliferation level of bone marrow stem cells was significantly higher than that on the hydroxyapatite coating. Our further study showed that the released SiO4 (4-) and Mg(2+) ions from bredigite coating as well as the formed nano-apatite layer on the coating surface might mainly contribute to the improvement of cell proliferation. The results indicated that the bredigite coating may be applied on orthopedic implants due to its excellent bonding strength, apatite mineralization and cytocompatibility.

In plain English

This laboratory study does not concern asbestos. The authors made a coating of bredigite, a calcium magnesium silicate ceramic, by plasma spraying it onto titanium alloy (Ti-6Al-4 V) for possible use on orthopedic implants. For comparison they also sprayed a hydroxyapatite (HA) coating. The coating was mainly crystalline bredigite with a small amount of amorphous material. Its bonding strength to the alloy ranged from 41.1 to 49.8 MPa and rose as the spraying current was increased. The authors noted this was much higher than the 15 MPa required by an international standard for HA coating implants. After 2 days in simulated body fluid, an apatite (bone-mineral-like) layer covered the coating. Rabbit bone marrow stem cells grew less on bredigite than on HA coating and blank controls after 1 day, but more after 3 and 7 days. The culture medium around bredigite held more magnesium and silicon. The authors speculated that these released ions may help stimulate cell growth. The authors concluded the coating may be used for orthopedic implants.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Laboratory (in vitro) materials study: preparation and testing of a plasma-sprayed ceramic coating, with cell culture tests
• Who was studied: Bredigite-coated and HA-coated titanium alloy samples; rabbit bone marrow mesenchymal stem cells cultured on them
• Exposure: Not an asbestos exposure. Plasma-sprayed bredigite (Ca7MgSi4O16) coating on Ti-6Al-4 V alloy, sprayed at currents of 550, 600 and 650 A, compared with a plasma-sprayed commercial hydroxyapatite (HA) coating
• Main results:
  • The coating's main crystal phase was bredigite, with a small amount of amorphous phase
  • Mean bonding strength of the bredigite coating to the alloy was 41.1 to 49.8 MPa and increased with plasma spraying current
  • The authors stated the bredigite coating's bonding strength was much higher than the 15 MPa requirement of ISO 13779-2 for bioactive HA coating implants
  • An apatite layer covered the bredigite coating after 2 days in simulated body fluid (SBF)
  • Calcium ion concentration in SBF with the bredigite coating was 2.5 times higher than in SBF without it
  • After 1 day, rabbit bone marrow stem cells proliferated less on bredigite coating than on HA coating and blank control
  • At 3 and 7 days, cells on bredigite coating proliferated more than on HA coating and blank control
  • Magnesium and silicon concentrations in culture medium with bredigite coating were significantly higher than with HA coating
• The authors' conclusion: The authors concluded that the bredigite coating on Ti-6Al-4 V may be used to prepare orthopedic implants because of its improved bonding strength, rapid apatite mineralization and cytocompatibility; they speculated that released Mg and Si ions may help stimulate cell proliferation

Topics

The National Library of Medicine indexes this study under subjects our site covers: Tremolite.

Medical terms in this study, explained in our Lexicon: Silicate, Simulated Body Fluid, STEM.

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