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

Our plain-English summary of 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, by M. Razavi, M. Fathi, O. Savabi, et al (Annals of Biomedical Engineering, 2014).

The study

• Authors: M. Razavi, M. Fathi, O. Savabi, D. Vashaee, L. Tayebi
• Journal: Annals of Biomedical Engineering
• Published: 2014;42(12):2537-50
• Cited by: 16 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

This research explored the influence of surface modification of AZ91 Mg alloy on the biodegradation, bioactivity, mechanical integrity and cytocompatibility of the alloy. For this purpose, a nanostructured bredigite (Ca7MgSi4O16) ceramic coating was prepared on biodegradable AZ91 Mg alloy through anodic spark deposition and electrophoretic deposition method. The phase composition and surface morphology of the coated alloy were characterized by X-ray diffraction, scanning electron microscope and transmission electron microscope. The properties of samples were investigated by electrochemical measurements, immersion test, compression examination and cell culturing. The results showed that the degradation resistance, bioactivity, mechanical integrity and cytocompatibility of biodegradable Mg alloy were improved by the anodic spark deposition and electrophorretic deposition of the nanostructured bredigite coating. Therefore, the nanostructured bredigite ceramic coating is identified as a good coating for AZ91 Mg alloy for the purpose of making biodegradable metallic orthopedic implants.

In plain English

This laboratory study did not concern asbestos. The authors coated AZ91, a magnesium alloy being studied for biodegradable orthopedic implants, with a nanostructured bredigite ceramic (Ca7MgSi4O16). The coating was applied over an anodic spark deposition (ASD) layer using electrophoretic deposition. They compared uncoated AZ91, ASD-only and bredigite/ASD samples in simulated body fluid and in cultures of L-929 fibroblast cells, using three samples per experiment. After 672 hours of immersion, the text reported weight loss of about 67 mg for uncoated AZ91, compared with 42 mg for ASD and 16 mg for bredigite/ASD samples. The matching figure labels weight loss in mg/cm2, so the unit is unclear. After 4 weeks of immersion, compressive strength fell from 230 MPa to 100, 130 and 220 MPa for those three groups. Cell viability on bredigite/ASD samples rose from 132% of control at 2 days to 150% at 7 days, while on uncoated AZ91 it went from 50% to 58%. The authors concluded that the coating increased the alloy's degradation resistance, bioactivity, mechanical integrity and cytocompatibility.

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 (coating experiments, corrosion, immersion, compression and cell-culture tests); not an asbestos study
• Who was studied: AZ91 magnesium alloy samples (uncoated, ASD-coated, and bredigite/ASD-coated) and L-929 fibroblast cells cultured on them; three samples per experiment
• Exposure: Nanostructured bredigite (Ca7MgSi4O16) ceramic coating applied by anodic spark deposition (ASD) followed by electrophoretic deposition (EPD), compared with ASD alone and uncoated alloy; no asbestos exposure
• Main results:
  • Polarization resistance (Rp) ranked bredigite/ASD coating (16210.1 ohm) above ASD (957.2 ohm) and AZ91 (305.5 ohm)
  • The text gives weight loss of uncoated AZ91 after 672 h of immersion in simulated body fluid as approximately 67 mg. The Figure 4a axis is labelled mg/cm2, so the unit is inconsistent.
  • The text gives total weight loss after 4 weeks as 42 mg for ASD samples and 16 mg for bredigite/ASD-coated samples (figure axis in mg/cm2)
  • Magnesium ion release stabilized at 275, 130 and 40 ppm for AZ91, ASD and bredigite/ASD samples, respectively
  • Compressive strength changed from 230 MPa before immersion to 100 (AZ91), 130 (ASD) and 220 MPa (bredigite/ASD) after 4 weeks of immersion
  • Cell viability on bredigite/ASD samples increased from 132% of control at 2 days to 150% at 7 days (AZ91: 50% to 58%; ASD: 70% to 85%)
  • Culture medium pH after 7 days was 9.5 (AZ91), 8.8 (ASD) and 7.8 (bredigite/ASD)
  • After 672 h of immersion, the bredigite-coated sample surfaces were fully covered with precipitates that the authors interpreted as bioactive minerals
• The authors' conclusion: The authors concluded that the degradation resistance, bioactivity, mechanical integrity and cytocompatibility of the biodegradable Mg alloy were increased by the ASD and EPD bredigite coating

Topics

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

Medical terms in this study, explained in our Lexicon: Deposition, X-Ray Diffraction (XRD).

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