Preparation and characteristics of a calcium magnesium silicate (bredigite) bioactive ceramic

Our plain-English summary of Preparation and characteristics of a calcium magnesium silicate (bredigite) bioactive ceramic, by C. Wu, J. Chang, J. Wang, et al (Biomaterials, 2005).

The study

• Authors: C. Wu, J. Chang, J. Wang, S. Ni, W. Zhai
• Journal: Biomaterials
• Published: 2005;26(16):2925-31
• Cited by: 92 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

In this study, new bredigite (Ca7MgSi4O16) ceramics were prepared by sintering sol-gel-derived bredigite powder compacts at 1350 degrees C for 8 h. The bending strength, fracture toughness and Young's modulus were about 156 MPa, 1.57 MPa m(1/2) and 43 GPa, respectively. The in vitro bioactivity of the bredigite ceramics was evaluated by investigating the apatite-formation ability in simulated body fluid (SBF) and the effect of ionic products from bredigite dissolution on the mouse fibroblasts cell line L929. In addition, the in vitro biocompatibility of the bredigite ceramics was evaluated by osteoblasts adhesion and proliferation assay. The results showed that bredigite ceramics could induce HAp formation in SBF. The products from bredigite dissolution significantly promoted cell growth at a certain concentration range. Furthermore, osteoblasts adhered and spread well on bredigite ceramics, and osteoblasts proliferation on bredigite ceramics was obvious.

In plain English

This laboratory study does not concern asbestos. It describes a new ceramic intended for bone repair. The authors made bredigite, a calcium magnesium silicate, by pressing a sol-gel powder and heating it at 1350 degrees C for 8 hours. The resulting ceramic had a bending strength of about 156 MPa, a fracture toughness of about 1.57 MPa m1/2 and a Young's modulus of about 43 GPa. Discs soaked in simulated body fluid showed hydroxyapatite, a bone-like mineral, on their surface after 7 days; after 20 days the surface layer had a calcium-to-phosphorus ratio of about 1.65. Liquid extracted from bredigite was tested on mouse L929 fibroblast cells. At 6.25 to 50 mg/ml it gave significantly higher readings of living cells than the control after 3 and 7 days. At 100 and 200 mg/ml it gave lower readings after 7 days, indicating inhibited growth. Rat bone-forming cells (osteoblasts) attached to and spread on the ceramic, reaching 5500 cells/cm2 after 5 days. The authors concluded the ceramic showed good bioactivity and biocompatibility in the laboratory and may be usable for bone repair. They added that studies in living organisms (in vivo) are still needed.

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: In vitro laboratory materials study (preparation and testing of a ceramic, with cell-culture experiments)
• Who was studied: Bredigite (Ca7MgSi4O16) ceramic bars and discs; mouse fibroblast cell line L929; osteoblasts isolated from the skulls of newborn Sprague–Dawley rats
• Exposure: No asbestos exposure. Cells were exposed to diluted extracts from bredigite dissolution, at concentrations of 6.25 to 200 mg/ml, and osteoblasts were grown on bredigite ceramic discs.
• Main results:
  • The sintered bredigite ceramics had a bending strength of about 156 MPa, a fracture toughness of about 1.57 MPa m1/2 and a Young's modulus of about 43 GPa.
  • Characteristic hydroxyapatite peaks appeared on the bredigite ceramics after 7 days of soaking in simulated body fluid.
  • In ceramics soaked in simulated body fluid for 20 days, the hydroxyapatite (calcium-phosphate) surface layer had a Ca/P ratio of about 1.65, similar to stoichiometric hydroxyapatite.
  • For L929 cells, readings were significantly higher than the negative control (p less than 0.05) after 3 and 7 days at bredigite concentrations of 6.25 to 50 mg/ml.
  • For L929 cells, at 100 and 200 mg/ml readings were lower than the negative control after 7 days, indicating an inhibitory effect on cell growth.
  • Osteoblasts on the ceramic showed an elongated, flattened appearance after 24 hours of culture.
  • Osteoblast numbers on the ceramic increased significantly with culture time, reaching 5500 cells/cm2 after 5 days.
• The authors' conclusion: The authors concluded that bredigite ceramics possess good in vitro bioactivity and biocompatibility and may be used as bioactive bone repair materials.
• Limitations the authors state:
  • The authors stated that further in vivo studies are needed to explore whether these ceramics can be used as implant materials.

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, Fibroblast.

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