Infection free titanium alloy biomaterials by thiol based plasma polymerisation technique
Çökeliler, Dilek; Caner, Hakan; Saglam, Necdet; Göktas, Hilal; Topacli, Cafer; Mutlu, Mehmet
Turkey

The implantation of a biomaterial into the human body, and the subsequent damage caused to the tissues is known to increase susceptibility to infection and to activate host defenses, stimulating the release of inflammatory mediators, including oxygen radicals and lysosomal enzymes. Microbial adhesion to surfaces and the formation of a complex biofilm at the interface between a biomaterial and the biological environment are frequent reasons for sustained inflammatory processes and ultimate failure of biomedical devices such as vascular and urinary catheters, heart valves and prostheses. As biomedical materials, titanium and titanium alloys (Ti-6Al-4V) are superior to many materials such as stainless and so on, in terms of mechanical properties and biocompatibility. However, they are still not sufficient for prolonged clinical use because the biocompatibility of these materials must be improved. Hence, the development of surface modification is a real necessity for the biomedical community.
In this study, the prevention of the attachment of test microorganism on the Ti alloy based biomaterial surfaces by thiol and hydroxyl functional group containing monomer in plasma polymerization system was reported. The samples were modified by a plasma based electron beam generator in order to prepare anti-fouling surfaces. The precursor, 11-mercaptoundecanoic acid was used as plasma sources. The surface chemistry and topology of unmodified and modified samples were characterized by Fourier Transform Infrared Spectroscopy (FTIR) and Atomic Force Microscopy (AFM). Static contact angle measurements were performed to state the change of surface hydrophilicity.All samples were tested in-vitro environment with Staphylococcus epidermidis that was chosen as the bacteria strain in view of its significance for the pathogenesis of medical-device-related infections and this test was repeated after certain period of times in order to investigate the stability of the modified samples.
Plasma polymerized 11-mercaptoundecanoic acid film (PP MUA) was found alternative, stabile and simple method to create bacterial anti-fouling surfaces. The attachment of the model microorganism on the biomaterial surface prepared by PP MUA was reduced 95.3 % if compared to unmodified control surface.
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