Research Article Physicochemical Analysis of the Polydimethylsiloxane Interlayer Influence on a Hydroxyapatite Doped with Silver Coating C. L. Popa, 1,2 A. Groza, 3 P. Chapon, 4 C. S. Ciobanu, 1 R. V. Ghita, 1 R. Trusca, 5 M. Ganciu, 3 and D. Predoi 1 1 National Institute for Materials Physics, P.O. Box MG 07, Magurele, 077125 Bucharest, Romania 2 Faculty of Physics, University of Bucharest, 405 Atomistilor Street, P.O. Box MG1, 077125 Magurele, Romania 3 National Institute for Laser, Plasma and Radiation Physics, 409 Atomistilor Street, P.O. Box MG 36, Magurele, 077125 Bucharest, Romania 4 Horiba Jobin Yvon S.A., 16-18 rue du Canal, 91165 Longjumeau Cedex, France 5 S.C. METAV R&D S.A., 020011 Bucharest, Romania Correspondence should be addressed to A. Groza; andreea@infm.ro and D. Predoi; dpredoi@gmail.com Received 6 October 2014; Revised 15 December 2014; Accepted 15 December 2014 Academic Editor: Jen-Jie Chieh Copyright © 2015 C. L. Popa et al. Tis 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. We investigate by diferent complementary methods the processes occurring when a polydimethylsiloxane flm is used as interlayer for a silver doped hydroxyapatite coating. Te X-ray difraction and Fourier Transform Infrared Spectroscopy measurements show that the hydroxyapatite doped with silver is in a crystalline form and some SiO 4 4− ions formation takes place at the surface and in the bulk of the new hydroxyapatite doped with silver/polydimethylsiloxane composite layer. Te possibility of SiO 4 4− ions incorporation in the structure of silver doped hydroxyapatite by the mechanism of SiO 4 4− /PO 4 3− ions substitution is analysed. Te new formed silver doped hydroxyapatite/polydimethylsiloxane composite layer is compact, homogeneous, with no cracks as it was shown by Scanning Electron Microscopy and Glow Discharge Optical Emission Spectrometry. 1. Introduction Hydroxyapatite (HAp, Ca 10 (PO 4 ) 6 (OH) 2 ) is a biomaterial with a wide range of applications in medicine due to its biocompatibility, bioactivity, and osteoconductivity [1–4]. Hydroxyapatite has been used to fll a wide range of bony defects in orthopedic and maxillofacial surgeries and den- tistry [5–8]. It has also been widely used as a coating for metallic prostheses to improve their biological properties [9– 11]. From an antibacterial point of view, silver nanoparticles are widely used in medical devices and supplies such as wound dressings, scafold, skin donation, recipient sites, and sterilized materials in hospitals, medical catheters, contracep- tive devices, surgical instruments, bone prostheses, artifcial teeth, and bone coating. Recently, the use of inorganic antibacterial agents, like sil- ver or copper, incorporated in the structure of hydroxyapatite has been shown to be of great interest in the fght against microbes [4]. Hydroxyapatite (HAp) has a very high cation exchange rate with silver ions. Even if at high concentration the silver can be toxic, in small concentrations it has a broad spectrum of antibacterial activity for a wide range of microor- ganisms like viruses, bacteria, or fungi [2]. Terefore the optimization of the Ag concentration in the HAp structure is critical to guarantee an optimum antibacterial efect without cytotoxicity. Te most common technique to incorporate Ag into HAp structure is via an ion exchange method, in which the Ca ions in HAp are replaced by Ag ions while dipping the HAp coatings into AgNO 3 for a period of time [2]. Te limitation of this ion exchange method is that Ag will reside mostly on Hindawi Publishing Corporation Journal of Nanomaterials Volume 2015, Article ID 250617, 10 pages http://dx.doi.org/10.1155/2015/250617