Degradation, bioactivity, and cytocompatibility of diopside, akermanite, and bredigite ceramics

Our plain-English summary of Degradation, bioactivity, and cytocompatibility of diopside, akermanite, and bredigite ceramics, by C. Wu, J. Chang (Journal of Biomedical Materials Research. Part B, Applied Biomaterials, 2007).

The study

• Authors: C. Wu, J. Chang
• Journal: Journal of Biomedical Materials Research. Part B, Applied Biomaterials
• Published: 2007;83(1):153-60
• Cited by: 114 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

The aim of this study was to investigate the effect of three bioceramics in the CaO-SiO(2)-MgO systems with different composition on the in vitro degradation, bioactivity, and cytocompatibility. The degradation was evaluated through the activation energy of Si ion release from ceramics and the weight loss of the ceramics in Tris-HCl buffers. The in vitro bioactivity of the ceramics was investigated by analysis of apatite-formation ability in the simulated body fluid (SBF). The cytocompatibility was evaluated through osteoblast morphology and proliferation. The results showed that the activation energy of Si ion release increased and the degradation decreased from bredigite to diopside ceramics with the increase of Mg content, and the apatite-formation ability in SBF decreased. The Ca, Si, and Mg containing ionic products from three ceramics could stimulate cell proliferation at lower concentration, and inhibit cell proliferation with the increase of ion concentrations. Furthermore, osteoblasts could adhere, spread, and proliferate on three ceramic disks, and cell proliferation on diopside was more obvious than that on other two ceramic disks.

In plain English

This laboratory study tested three calcium-magnesium-silicate ceramics (diopside, akermanite and bredigite) proposed as bone-repair materials. It is not a study of asbestos. The authors measured how quickly each ceramic broke down in a buffer solution. They also tested whether a bone-like mineral (apatite) formed on each ceramic in a fluid that mimics blood plasma, and how bone-forming cells taken from newborn rats grew on the ceramics or in liquid extracts made from them. Bredigite broke down fastest and diopside slowest, with akermanite in between. The authors described breakdown falling as magnesium content rose. Apatite formation followed the same order, strongest on bredigite. Extracts at lower concentrations stimulated cell growth. At the highest concentration they gave no stimulation, and the bredigite extract held back growth. On the ceramic disks themselves, cells grew most on diopside. The authors concluded that magnesium content might be a key factor in breakdown and apatite formation. They said further animal studies are needed to confirm possible uses.

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 experiment comparing three ceramic materials, using chemical soaking tests and rat bone-cell culture
• Who was studied: Diopside, akermanite and bredigite ceramic disks and powders, and osteoblast-like (bone-forming) cells isolated from the skull bones (calvaria) of newborn Sprague-Dawley rats less than 2 days old
• Exposure: Three CaO-SiO2-MgO ceramics with different magnesium contents (diopside, akermanite, bredigite). Cells were exposed to ceramic powder extracts diluted to 100, 12.5 and 1.25 mg/mL, and were also grown directly on ceramic disks. No asbestos fibers were studied.
• Main results:
  • Activation energy for silicon release (higher means slower release) was lowest for bredigite (0.093 eV) and highest for diopside (0.349 eV). Akermanite was intermediate (0.185 eV in Table III).
  • After 28 days in buffer, bredigite showed the highest weight loss, diopside the lowest, and akermanite was intermediate.
  • Phosphorus in the simulated body fluid fell from 1.0 mM to 0.63 mM (diopside), 0.31 mM (akermanite) and 0.18 mM (bredigite) after 7 days. The authors took this as phosphorus being used up in apatite formation, with the highest-magnesium ceramic showing the lowest apatite-forming ability.
  • Extracts from all three ceramics stimulated rat osteoblast proliferation at 1.25 to 12.5 mg/mL.
  • At 100 mg/mL no stimulatory effect was seen, and the bredigite extract showed an inhibitory effect on cell proliferation.
  • Cells grown on the ceramic disks proliferated most on diopside and least on bredigite after 7 days, with akermanite intermediate.
• The authors' conclusion: The authors concluded that magnesium content might be one of the key factors affecting the breakdown and apatite-forming ability of these ceramics. They also concluded that silicon ions might be mainly responsible for the stimulation of osteoblast proliferation.
• Limitations the authors state:
  • The authors stated that further studies are required to determine how crystal structure relates to breakdown.
  • The authors stated that in vivo (living-animal) studies are still needed to confirm possible applications.

Topics

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

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

Related studies

• Preparation and characteristics of a calcium magnesium silicate (bredigite) bioactive ceramic — C. Wu, J. Chang, et al. (2005)
• A novel bioactive porous bredigite (Ca7MgSi4O16) scaffold with biomimetic apatite layer for bone tissue engineering — C. Wu, J. Chang, et al. (2007)
• Improvement of biodegradability, bioactivity, mechanical integrity and cytocompatibility behavior of biodegradable mg based orthopedic implants using nanostructured Bredigite (Ca7MgSi 4O 16) bioceramic coated via ASD/EPD technique — M. Razavi, M. Fathi, et al. (2014)
• Bioactive bredigite coating with improved bonding strength, rapid apatite mineralization and excellent cytocompatibility — D. Yi, C. Wu, et al. (2014)
• Synthesis and in vitro bioactivity of bredigite powders — C. Wu, J. Chang (2007)
• Stimulatory effects of the ionic products from Ca-Mg-Si bioceramics on both osteogenesis and angiogenesis in vitro — W. Zhai, H. Lu, et al. (2013)

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