Research Article In Vitro Evaluation of Bioactivity of Chemically Deposited Hydroxyapatite on Polyether Ether Ketone D. Almasi, 1,2 S. Izman, 1 M. Sadeghi, 3 N. Iqbal, 2 F. Roozbahani, 4 G. Krishnamurithy, 5,6 T. Kamarul, 6 and M. R. Abdul Kadir 2 1 Department of Manufacturing and Industrial Engineering, Faculty of Mechanical Engineering, Universiti Teknologi Malaysia, 81310 Skudai, Johor, Malaysia 2 Medical Devices & Technology Group (MEDITEG), Faculty of Bioscience and Medical Engineering, Universiti Teknologi Malaysia, 81310 Skudai, Johor, Malaysia 3 Faculty of Chemical Engineering, Universiti Teknologi Malaysia, 81310 Johor Bahru, Johor, Malaysia 4 Faculty of Bioscience and Medical Engineering, Universiti Teknologi Malaysia, 81310 Skudai, Johor, Malaysia 5 Institute of Translational Medicine, University of Liverpool, Sherrington Building, Liverpool L69 3GE, UK 6 Department of Orthopaedic Surgery, NOCERAL, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia Correspondence should be addressed to M. R. Abdul Kadir; raiq@biomedical.utm.my Received 30 September 2014; Revised 16 January 2015; Accepted 28 January 2015 Academic Editor: Bruce Milthorpe Copyright © 2015 D. Almasi et al. his is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Polyether ether ketone (PEEK) is considered the best alternative material for titanium for spinal fusion cage implants due to its low elasticity modulus and radiolucent property. he main problem of PEEK is its bioinert properties. Coating with hydroxyapatite (HA) showed very good improvement in bioactivity of the PEEK implants. However the existing methods for deposition of HA have some disadvantages and damage the PEEK substrate. In our previous study a new method for deposition of HA on PEEK was presented. In this study cell proliferation of mesenchymal stem cell and apatite formation in simulated body luid (SBF) tests were conducted to probe the efect of this new method in improvement of the bioactivity of PEEK. he mesenchymal stem cell proliferation result showed better cells proliferation on the treated layer in comparison with untreated PEEK. he apatite formation results showed the growth of the HA on the treated PEEK but there was not any sight of the growth of HA on the untreated PEEK even ater 2 weeks. he results showed the new method of the HA deposition improved the bioactivity of the treated PEEK in comparison with the bare PEEK. 1. Introduction Recently PEEK has been considered as an ideal choice for spinal fusion cage due to its low modulus of elasticity, excel- lent chemical stability, resistance to radiation used in ster- ilization procedures, transparency to radio waves, compati- bility with reinforcing agent, and so forth. Food and Drug Administration of United States (FDA) accepted the carbon- iber-reinforced PEEK (CFR-PEEK) for spinal fusion cages for human use in 1990s. here is one big disadvantage of PEEK for orthopedic application, which is its low bioactivity. For enhancement of the bioactivity of PEEK, several methods have been proposed such as plasma surface treatment [1], laser surface modiica- tion [2], deposition of the HA coating layer [3], and com- pounding with bioactive material such as HA and producing bioactive composites [4]. he current commercial method for improving the bioactivity of PEEK is deposition of HA via plasma spraying method which has some disadvantages due to the high temperature which is used during the deposition of the HA coating layer and crystallization of the coated HA [3]. In our previous study the HA crystalline particles were deposited on PEEK and eliminate high temperature in the deposition process [5]. In this study the bioactivity of the HA coated samples via chemically deposition method was evaluated by in vitro study. Hindawi Publishing Corporation International Journal of Biomaterials Volume 2015, Article ID 475435, 5 pages http://dx.doi.org/10.1155/2015/475435