Optimisation of fluorapatite coating synthesis applied to a biodegradable substrate

ABSTRACT

Fluorapatite was synthesised using the sol–gel route at three different pH values and aged for a number of days. The coating that was determined to be of optimal morphology was then applied to a pure iron substrate and to an austenitic stainless steel, the latter serving as a control. Deposited fluorapatite coatings were characterised by means of X-ray diffraction and Fourier transform infrared spectroscopy. Crystalline fluorapatite was successfully produced at temperatures as low as 250°C. Temperatures of 250°C and higher caused carbonated fluorapatite, present at 150°C, to transform into fluorapatite. Neutralisation of the sol before coating was found to give rise to a less soluble product when immersed in Hank’s solution at 37°C and 5% CO₂. Coatings on pure iron and stainless steel substrates were produced by neutralising the sol to pH 7 and heat treatment at 250°C. This generated a morphology which could potentially aid in cellular attachment.

KEYWORDS:

• Fluorapatite
• bioresorbable
• coating
• degradable
• synthesis
• powder
• sol–gel
• optimisation

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

Malcolm Caligari Conti http://orcid.org/0000-0001-8014-6592

Pierre Schembri-Wismayer http://orcid.org/0000-0001-6340-9063

Emmanuel Sinagra http://orcid.org/0000-0002-4742-7285

Diego Mantovani http://orcid.org/0000-0001-9672-895X

Joseph Buhagiar http://orcid.org/0000-0001-6517-7331

Notes

1 Osteoinduction: Process by which osteogenesis is induced.

Additional information

Funding

Malcolm Caligari Conti is funded by the REACH HIGH Scholars Programme. The research work disclosed in this publication is partially funded by the REACH HIGH Scholars Programme – Post-Doctoral Grants. The grant is part-financed by the European Union, Operational Programme II – Cohesion Policy 2014–2020 ‘Investing in human capital to create more opportunities and promote the wellbeing of society’ – European Social Fund.