Papers by Author: Serena Best

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Authors: Qian Tang, Roger Brooks, Serena Best
Abstract: Hydroxyapatite and silicon-substituted hydroxyapatite powers were prepared in-house through a wet precipitation method and then vacuum plasma sprayed onto Ti-6Al-4V discs. Two plasma gun input powers were employed, 37 kW and 40 kW. All coatings were nearly phase pure, except small traces of impurities (TTCP, -TCP and CaO). Coatings prepared under the lower plasma gun input power had lower crystallinity. In vitro studies showed that human osteoblast-like cells attached and spread very well on all coated discs. Among the four kinds of discs, SiHAC37 was the most supportive to cell growth.
Authors: Z. Yang, E.S. Thian, Serena Best, Ruth Cameron
Abstract: α-tricalcium phosphate (α-TCP) was prepared by a wet precipitation reaction between calcium hydroxide and orthophosphoric acid solutions. The as-synthesised powder was then characterised using a Scanning Electron Microscope (SEM) equipped with Energy Dispersive Spectroscope (EDS), X-ray Diffraction (XRD) and Fourier Transform Infrared Spectroscope (FTIR). Analyses revealed that a phase-pure powder with a Ca/P ratio of 1.5 was produced. In addition, nanosized α-TCP particles of diameter ~ 70 nm were agglomerated to form larger particles of 10μm in diameter. It was found that by the combination of attritor milling and solution evaporation, the agglomerates of α-TCP nanoparticles could be broken down, and distributed evenly within the poly(D,L-lactic-co-glycolic acid) (PLGA) matrix. Thus, a α-TCP/PLGA nanocomposite was successfully produced by a modified solution evaporation method at room temperature followed by hot pressing at 150 °C. The achievable ceramic loading was approximately 38 wt.%, which was confirmed by thermal gravimetric analysis (TGA).
Authors: Z. Yang, E.S. Thian, Roger A. Brooks, Neil Rushton, Serena Best, Ruth Cameron
Abstract: In this study, a biocomposite comprising nanostructured α-tricalcium phosphate (α-TCP) in a poly(D,L-lactic-co-glycolic acid) (PLGA) matrix was fabricated by a modified solution evaporation method. As a potential temporary bone fixation and substitution material, its bioactivity was evaluated by its ability to form bone-like apatite layer in simulated body fluid (SBF). Owing to the increased surface area covered by the osteoconductive bioceramic of α-TCP, rapid apatite formation was observed. After 7 days of immersion, enhanced nucleation of apatite was observed on the nanocomposite. At day 14, dense lamellar-like apatite was formed on the nanocomposite whilst apatite nucleation had only just started to develop on the surface of pure PLGA. At the same time, a preliminary in-vitro cell culture study was conducted using human osteoblast-like (HOB) cells. A significant increase in cell number with culturing time was observed for the nanocomposite. After 9 days incubation, a confluent lamellar-like apatite layer was formed on the composite surface. This apatite layer was also shown beneath the proliferating HOB cells at Day 16.
Authors: J.A. Juhász, Kawashita Masakazu, Noboru Miyata, Tadashi Kokubo, Takashi Nakamura, Serena Best, William Bonfield
Authors: Marcelo Henrique Prado da Silva, Gloria Dulce de Almeida Soares, Carlos Nelson Elias, Iain R. Gibson, Serena Best
Authors: C.M. Botelho, Roger A. Brooks, Serena Best, M.A. Lopes, José D. Santos, Neil Rushton, William Bonfield
Authors: J.H. Robinson, Serena Best
Abstract: Precipitation routes for HA production result in the formation of suspensions of nano-scale hydroxyapatite particles in water. During this work, suspensions of phase-pure and carbonate-substituted hydroxyapatite were produced using a precipitation reaction with calcium hydroxide and orthophosphoric acid as reactants. The chemistry of the apatites was analysed using XRD and FTIR after heat treatment in various atmospheres and the particle morphology investigated using TEM. The thermal stability of the carbonate HA was found to be significantly less than the phase-pure HA and dependent upon the heat-treatment atmosphere. Suspensions were used directly for replication of polymer foam templates with a dip-coating technique. Good replication of the foam structure was achieved with the phase pure hydroxyapatite, but no structural integrity was achieved with the carbonate-HA structure possibly a result of limits on the sintering temperature.
Authors: Nelesh Patel, E.L. Follon, Iain R. Gibson, Serena Best, William Bonfield
Authors: C.M. Botelho, D.J. Stokes, Roger A. Brooks, Serena Best, M.A. Lopes, José D. Santos, Neil Rushton, William Bonfield
Authors: E.S. Thian, Z. Ahmad, Jie Huang, Mohan J. Edirisinghe, S.N. Jayasinghe, D.C. Ireland, Roger A. Brooks, Neil Rushton, William Bonfield, Serena Best
Abstract: Fine nanoapatite relics were deposited on glass substrates by electrohydrodynamic atomisation, using nanohydroxyapatite (nHA), nano-carbonated hydroxyapatite (nCHA) and nanosilicon- substituted hydroxyapatite (nSiHA) suspensions. These electrosprayed nanoapatites were evaluated in-vitro using simulated body fluid (SBF) and human osteoblast (HOB) cells. The SBF study revealed that newly-formed apatite layers were observed on the surface of the relics. Furthermore, enhanced HOB cell growth was observed on each of the nanoapatites at all time points. Hence, this work demonstrated that electrosprayed nanoapatites offer considerable potential as biomaterials.
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