Synthesis and in-vitro antibacterial properties of a functionally graded Ag impregnated composite surface.

Silver is considered promising in medical devices to prevent infection due to its excellent properties of broad antibacterial spectrum and persistent antibacterial activity. Herein, silver impregnated functionally graded composite surfaces have been developed by a novel duplex plasma deposition technique, which combines the double glow sputtering process and active screen plasma nitriding process. The composite surfaces include a surface antibacterial layer and a bottom supporting layer, which are deposited simultaneously. The functionally graded structure endows the composite surfaces with antibacterial activity, combined with improved wear resistance. The multilayer structures were observed by scanning electron microscopy, and the graded distribution of silver and nitrogen was verified by glow discharge optical emission spectroscopy. X-ray diffraction and X-ray photoelectron spectroscopy were used to analyze the microstructures and chemical states of the components. Results from physical properties tests indicated that the composite surfaces have increased hardness, lower contact angles, excellent scratch resistance and wear resistance. The in-vitro antibacterial tests using the Gram-negative E. coli. NCTC 10418 also showed that over 99% of bacteria were killed after 5 h contacting with the composite surface.

[Titanium oxide layer on biomedical titanium alloy deposited by ion beam enhanced deposition].

Ion beam enhanced deposition (IBED) has been applied to prepare titanium oxide layer on titanium alloy (Ti6A14V) in order to improve its biocompatibility. The layer on titanium alloy is even, and the elements Al and V in substrate are not detected. The layer is composed of TiO containing nitrogen oriented along (111) plane. The critical load of the layer in scratch test is 16.8 N. Morphological observation reveals the layer ends in a failure caused by plastic deformation.