Major problems with biomedical devices in particular implants located in nonsterile environments concern: (i) excessive immune response to the implant, (ii) development of bacterial biofi lms, and (iii) yeast and fungi infections. An original multifunctional coating that addresses all these issues concomitantly is developed. A new exponentially growing polyelectrolyte multilayer fi lm based on polyarginine (PAR) and hyaluronic acid (HA) is designed. The fi lms have a strong inhibitory effect on the production of infl ammatory cytokines released by human primary macrophage subpopulations. This could reduce potential chronic infl ammatory reaction following implantation. Next, it is shown that PAR, due to its positive charges, has an antimicrobial activity in fi lm format against Staphylococcus aureus for 24 h. In order to have a long-term antimicrobial activity, a precursor nanoscale silver coating is deposited on the surface before adding the PAR/HA fi lms. Moreover, the PAR/HA fi lms can be easily further functionalized by embedding antimicrobial peptides, like catestatin (CAT), a natural host defense peptide. This PAR/HA+CAT fi lm proves to be effective as an antimicrobial coating against yeast and fungi and its cytocompatibility is also assessed. Finally, this all-in-one system constitutes an original strategy to limit infl ammation and prevents bacteria, yeast, and fungi infections.

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Plasma-spray (PS) is a classical technique usually employed to cover orthopaedic titanium implant surfaces with hydroxyapatite (HA - Ca(10)(PO(4))(6)(OH)(2)). The objective of the current study is to investigate the structure and microstructure of HA plasma-spray 50 mum thick coating on titanium alloy (Ti-6Al-4 V) and residual stress due to processing in the substrate and in HA coating. The structure of the coatings was determined by high-energy synchrotron X-ray diffraction in energy dispersive (HESXRD), selected area electron diffraction (saed), Scanning Electron Microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR). No impurity phases in the HA were identified by HESXRD to keep away from the decomposition of HA at high temperature. hcp phase of HA substrate was detected with slight amorphous background. FTIR spectrum of a HA powder shows a typical spectrum for HA material with the characteristic phosphate peaks for HA at wavenumbers of 1090, 1052, 963, 602, and 573 cm(-1) are present. The morphology of HA powder observed by SEM exhibits grains of ca. 0.1 mum well-adapted for cell proliferation. HA/Ti-6Al-4 V interface observed by cross-section scanning and transmission electron microscopy (TEM) presents microcracks. Residual stresses were analyzed by sin(2) Psi X-ray diffraction method on titanium substrates and HA coating. Although the Ti substrates are in a slightly tensile residual state, the coated ones show a compressive state.