Bacterial biofilms and biomineralisation on titanium

Wang, Anqi (2011). Bacterial biofilms and biomineralisation on titanium. University of Birmingham. Ph.D.

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Abstract

This study investigated bacterial interactions with titanium, and evaluated the use of Serratia biomineralisation to produce a hydroxyapatite (HA) coating on titanium. Adherence of Gram-positive Staphylococcus epidermidis and Streptococcus sanguinis and Gram-negative Serratia sp. NCIMB 40259 and Escherichia coli was compared on commercially pure titanium, Ti6Al4V alloy, pure aluminium and pure vanadium. Grain boundaries, grain orientation and alloy phase structure did not influence adhesion or early proliferation. Adherence of all four strains was equivalent on pure titanium and Ti6Al4V and inhibited on pure aluminium. Serratia biomineralisation was used to introduce a crystalline coating on Al\(_2\)O\(_3\) grit blasted titanium discs and a porous titanium mesh. The porous coating consisted of micro-scale spheres composed of nano-scale calcium deficient HA. Embedded alumina particles and alkali treatment did not noticeably alter precipitation of Serratia HA, nor the structure of the coating in comparison with non-treated substrates. Coatings were retained after sintering at 800\(^\circ\)C in argon, although the original curved plate-like crystals changed to nano-scale β-tricalcium phosphate particles. A phosphorous-rich diffusion zone formed at the coating-titanium interface. This biomineralised coating may have applications for coatings of implants in non load-bearing sites, and other non-clinical applications where a high surface area is the major concern.

Type of Work:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

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