@article{rabiei_sandukas_2013, title={Processing and evaluation of bioactive coatings on polymeric implants}, volume={101}, ISSN={["1552-4965"]}, DOI={10.1002/jbm.a.34557}, abstractNote={Polyetheretherketone (PEEK) is a high‐performance polymer with advantages over metallic biomaterials for application in spinal implants. In this study, hydroxyapatite (HA) coatings were deposited onto PEEK substrates using radio‐frequency magnetron sputtering for the purpose of improving bioactivity. An intermediate coating layer of yttria‐stabilized zirconia (YSZ) was first deposited onto the PEEK substrates to provide heat shielding during subsequent post‐deposition heat treatment to prevent degradation of PEEK substrates and coating/substrate interface. Plasma activation of the PEEK substrate surfaces before deposition resulted in a significant increase in coating adhesion strength. Post‐deposition heat treatments of microwave and hydrothermal annealing were studied with the goal of forming crystalline HA without the use of high temperatures required in conventional annealing. Microstructural and compositional analyses by scanning electron microscopy (SEM) and X‐ray diffraction revealed that the YSZ layer exhibited a crystalline structure as‐deposited, with columnar grains oriented along the growth direction, whereas the HA layer was shown to be amorphous as‐deposited. After microwave annealing, the HA coating exhibited a columnar crystalline microstructure, similar to that of the underlying YSZ crystalline layer; XRD analysis confirmed a crystalline HA phase in the coating. It is suggested that the existence of the crystalline YSZ layer aids in the formation of the HA layer upon heating, possibly lowering the activation energy for crystallization by providing nucleation sites for HA grain formation. Cell culture tests showed a significant increase in initial cell attachment and growth on the microwave‐annealed coatings, compared with uncoated PEEK and amorphous HA surfaces. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 101A: 2621–2629, 2013.}, number={9}, journal={JOURNAL OF BIOMEDICAL MATERIALS RESEARCH PART A}, author={Rabiei, Afsaneh and Sandukas, Stefan}, year={2013}, month={Sep}, pages={2621–2629} }
 @article{bai_sandukas_appleford_ong_rabiei_2012, title={Antibacterial effect and cytotoxicity of Ag-doped functionally graded hydroxyapatite coatings}, volume={100B}, ISSN={["1552-4981"]}, DOI={10.1002/jbm.b.31985}, abstractNote={Abstract}, number={2}, journal={JOURNAL OF BIOMEDICAL MATERIALS RESEARCH PART B-APPLIED BIOMATERIALS}, author={Bai, Xiao and Sandukas, Stefan and Appleford, Mark and Ong, Joo L. and Rabiei, Afsaneh}, year={2012}, month={Feb}, pages={553–561} }
 @article{sandukas_yamamoto_rabiei_2011, title={Osteoblast adhesion to functionally graded hydroxyapatite coatings doped with silver}, volume={97A}, ISSN={["1552-4965"]}, DOI={10.1002/jbm.a.33081}, abstractNote={Abstract}, number={4}, journal={JOURNAL OF BIOMEDICAL MATERIALS RESEARCH PART A}, author={Sandukas, Stefan and Yamamoto, Akiko and Rabiei, Afsaneh}, year={2011}, month={Jun}, pages={490–497} }
 @article{bai_sandukas_appleford_ong_rabiei_2009, title={Deposition and investigation of functionally graded calcium phosphate coatings on titanium}, volume={5}, ISSN={["1878-7568"]}, DOI={10.1016/j.actbio.2009.05.013}, abstractNote={A series of calcium phosphate coatings with graded crystallinity were deposited onto heated titanium substrates using ion beam assisted deposition. The microstructure of the coating was examined using transmission electron microscopy (TEM). The coating thickness was observed to be in a range of 594-694 nm. The degree of crystallinity and microstructural grain size of the coating showed a clear decrease with increasing distance from the substrate-coating interface. Fourier transform infrared spectroscopy (FTIR) confirmed the presence of PO(4)(3-), and X-ray photoelectron spectroscopy (XPS) analysis on the coating top surface showed that the atomic Ca/P ratio was in the range of 1.52+/-0.15 to 1.61+/-0.07. The biological response to the coatings was also evaluated using an osteoblast precursor cell culture test. More cells and a higher integrin expression of cell attachment sites were observed on the coating surface when compared to the control group (blank titanium surface). The pull-off test showed average adhesion strengths at the coating-substrate interface to be higher than 85.12+/-5.37 MPa. Nanoindentation tests indicated that the Young's moduli of all coatings are higher than 91.747+/-3.641 GPa and microhardness values are higher than 5.275+/-0.315 GPa. While the adhesion strength results helped us to identify the best setup for substrate temperature and processing parameters to begin the deposition, the culture test and XPS results helped identifying the optimum parameters for the last stage of deposition. TEM, X-ray diffraction, FTIR and nanoidentation results were used to further evaluate the quality of the coating and optimization of its processing parameters.}, number={9}, journal={ACTA BIOMATERIALIA}, author={Bai, Xiao and Sandukas, Stefan and Appleford, Mark R. and Ong, Joo L. and Rabiei, Afsaneh}, year={2009}, month={Nov}, pages={3563–3572} }