Synthesis and in vitro bioactivity of bredigite powders

Our plain-English summary of Synthesis and in vitro bioactivity of bredigite powders, by C. Wu, J. Chang (Journal of Biomaterials Applications, 2007).

The study

• Authors: C. Wu, J. Chang
• Journal: Journal of Biomaterials Applications
• Published: 2007;21(3):251-63
• Cited by: 26 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Pure bredigite (Ca7MgSi4O16) powders are synthesized by the sol-gel method. The bredigite powders are composed of polycrystalline particles with dimensions of 1-10 micro m. The in vitro bioactivity of the bredigite powders are examined by evaluation of hydroxyapatite (HAp) formation ability in simulated body fluid (SBF) and the effect of ionic products from bredigite dissolution on osteoblast proliferation. The results showed that bredigite induced the formation of nanocrystalline HAp after soaking in SBF for 10 days. The Ca, Si, and Mg ions from bredigite dissolution at a certain concentration range stimulates osteoblast proliferation. Our study indicates that bredigite is bioactive and might be used for preparation of new biomaterials.

In plain English

This laboratory study is not about asbestos. It concerns bredigite, a calcium magnesium silicate ceramic that the authors studied as a possible material for repairing bone. The authors made bredigite powder chemically by a sol-gel method. Powder heated to 1000 degrees C still contained some akermanite, while powder heated to 1150 degrees C was pure bredigite. They soaked the powder for 10 days in simulated body fluid, a solution with ion levels similar to human blood plasma. Hydroxyapatite, the mineral found in bone, formed throughout the powder rather than only on its surface, as crystallites about 50 nm across. The authors also grew bone-forming cells (osteoblasts) from newborn rats in culture medium that had been in contact with the powder. Within a certain range of calcium, silicon and magnesium concentrations, this medium stimulated cell growth after 7 days. At the second-highest concentration tested, the cell measurement was lower than in the untreated control. The authors concluded that bredigite was bioactive and might be a potential candidate for tissue repair biomaterials.

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 and cell-culture experiment: synthesis of bredigite powder, soaking in simulated body fluid, and testing of powder dissolution products on cultured rat osteoblasts
• Who was studied: No people were studied. The test materials were synthetic bredigite powders and osteoblasts isolated from the calvaria (skull bones) of neonatal Sprague-Dawley rats less than 2 days old. The article states no number of animals.
• Exposure: No asbestos exposure. The powder was soaked in simulated body fluid at 1.5 mg/ml for 10 days. Osteoblasts were cultured with dissolution extracts made at 200 mg of bredigite per ml of medium, then diluted (from undiluted down to 1/320000) and tested for 1, 3 and 7 days.
• Main results:
  • Powder calcined at 1000 degrees C contained an akermanite impurity.
  • Powder calcined at 1150 degrees C was pure bredigite.
  • After 10 days in simulated body fluid, hydroxyapatite peaks appeared and the bredigite peaks disappeared. The authors interpreted this as bredigite inducing hydroxyapatite formation.
  • When the soaked powder was ground, only hydroxyapatite peaks remained, indicating that the hydroxyapatite was a bulk phase rather than a surface layer.
  • The hydroxyapatite crystallites that formed were about 50 nm in diameter.
  • Calcium, magnesium and silicon concentrations in the simulated body fluid rose with soaking time, while phosphorus fell. The authors attributed the fall in phosphorus to hydroxyapatite formation.
  • Dissolution extracts within a certain range of calcium, silicon and magnesium ion concentrations stimulated osteoblast proliferation after 7 days of culture.
  • When the ion concentrations reached 0.28 mM calcium, 9.95 mM silicon and 0.24 mM magnesium (extract B, the second-highest concentration), the optical density of osteoblasts was lower than that of the blank control (p less than 0.05).
• The authors' conclusion: The authors concluded that bredigite was bioactive and might be a potential candidate as a tissue repair biomaterial.
• Limitations the authors state:
  • The authors suggested that chemical composition matters more than crystal structure in determining the bioactivity of these calcium-silicon ceramics. They stated that further work is needed to confirm this.

Topics

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

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

Related studies

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• Preparation and characteristics of a calcium magnesium silicate (bredigite) bioactive ceramic — C. Wu, J. Chang, et al. (2005)
• Mechanical and cytotoxicity evaluation of nanostructured hydroxyapatite-bredigite scaffolds for bone regeneration — M. Eilbagi, R. Emadi, et al. (2016)
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• Bioactive bredigite coating with improved bonding strength, rapid apatite mineralization and excellent cytocompatibility — D. Yi, C. Wu, et al. (2014)

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