Title: Effect of heat treatment of nano-hydroxyapatite coatings prepared using electrohydrodynamic deposition

Authors: Xiang Li, Jie Huang, Mohan Edirisinghe, Garrit Koller, Lucy Di Silvio, Tara Renton, Minoo Esat, William Bonfield

Addresses: Department of Mechanical Engineering, University College London, Torrington's Place, London, WC1E 7JE, UK. ' Department of Mechanical Engineering, University College London, Torrington's Place, London, WC1E 7JE, UK. ' Department of Mechanical Engineering, University College London, Torrington's Place, London, WC1E 7JE, UK. ' Biomaterials, Biomimetics and Biophotonics, King's College Dental Institute at Guy's, King's and St. Thomas' Hospitals, Floor 17, Guy's Tower, London, SE1 9RT, UK; Oral Surgery, King's College Dental Institute at Guy's, King's and St. Thomas' Hospitals, Bessemer Road, London, SE5 9RS, UK. ' Biomaterials, Biomimetics and Biophotonics, King's College Dental Institute at Guy's, King's and St. Thomas' Hospitals, Floor 17, Guy's Tower, London, SE1 9RT, UK. ' Oral Surgery, King's College Dental Institute at Guy's, King's and St. Thomas' Hospitals, Bessemer Road, London, SE5 9RS, UK. ' Furlong Research Charitable Foundation, Lister House, 11–12 Wimpole Street, London, W1G 9ST, UK. ' Department of Mechanical Engineering, University College London, Torrington's Place, London, WC1E 7JE, UK; Department of Materials Science and Metallurgy, University of Cambridge, Pembroke Street, Cambridge, B2 QZ, UK

Abstract: Electrohydrodynamic spraying has recently emerged as a powerful method of producing nano-structured hydroxyapatite (nHA) coatings for biomedical implants. To enhance the mechanical properties of these coatings, a subsequent heat treatment is normally needed. However, whether this process significantly influences the coated surface morphology and cellular responses still needs to be systematically studied and documented. In this investigation, the morphology, composition and resultant surface roughness of the nHA coating surfaces were examined, prior to in vitro cytocompatibility, proliferation and cell morphological assessments using primary alveolar human osteoblast-like (aHOB) cells. After heat treatment of nHA coatings prepared using electrohydrodynamic spraying, it was found that the coated surface roughness reduced from a pre heat treated average of 4.2 μm to a post heat treated roughness of 2.9 μm, 2.5 μm and 2.1 μm at 500°C, 700°C and 900°C, respectively. The in vitro study determined a favourable osteoblast response to all substrates examined, with no statistical difference between the samples examined, as determined by the AlamarBlue proliferation assay over 21 days in culture. Confocal microscopy and scanning electron microscopy further demonstrated cell proliferation and adhesive adaptation on the experimental substrates.

Keywords: electrohydrodynamic spraying; nano-hydroxyapatite coatings; heat treatment; morphology; in vitro study; nanomaterials; nanotechnology; biomedical implants; medical implants; surface morphology; surface roughness; osteoblast response; biomaterials.

DOI: 10.1504/IJNBM.2009.028338

International Journal of Nano and Biomaterials, 2009 Vol.2 No.6, pp.477 - 493

Published online: 16 Sep 2009 *

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