In recent years the development of new and more sophisticated biomaterials have led to the production of different types of implants and prostheses that effectively replace injured or malfunctioning body parts. As a result, there has been an increasing use of these dental, cardiovascular and synthetic substitutes.
The Ti6Al4V alloy has been widely investigated as an implant biomaterial because of its strength, high density and resistance to corrosion processes, as well as a good osseointegration capability.
However, due to its high surface roughness, the alloy is prone to adhesion of both Gram-negative and Gram-positive bacteria, such as P. aeruginosa and S. aureus, respectively. Bacterial adhesion on the surface of titanium-based medical devices begins with the formation of weak Van der Waals bonds. (Rautray et al., 2010) If these pathogens are not promptly removed, they begin to excrete a glue-like substance that anchors them more firmly, and accumulation of new bacteria in this scaffold, called biofilm, occurs. Biofilms are formed by a complex polymeric matrix that protects the pathogens from antibiotics. Hence, once the infection has taken place and the biofilm is formed, it is very difficult to eradicate. These events may ultimately lead to implant failure and the need for its removal, with a high social and economic cost associated. (Ando et al., 2010)
In order to mitigate the proliferation of bacterial biofilms functionalisation and anchoring of bactericidal compounds on the biomaterial have been reported. (Ang et al., 2016)
Some 2-aminoimidazoles, isolated from marine sponges of the genus Leucetta, show antibiotic activity against various pathogenic bacteria (Mai, T. et al. 2015; Žula et al., 2015). In previous studies, it has been observed that 2-aminoimidazole derivatives bearing halide atoms in positions 4 and 5 inhibit by 90% the formation of bacterial biofilms of S. aureus (Fung et al., 2014).
With all this in mind, we have reasoned that a chloro-substituted aminoimidazol would represent an interesting molecule to be anchored on the biomaterial surface, and that it might give the alloy some antibacterial protection.
Hence, the objectives of this piece of work are:
- To synthesise 2-amino-4- (4-chlorophenyl) imidazole using conventional as well as microwave assisted procedures.
- To modify the Ti6Al4V surface and by passivation and silanisation processes, to enable it to generate a high density of functional groups of amino or carbonyl type to facilitate interaction with the 2-aminoimidazole.
- To anchor the 2-amino-4- (4-chlorophenyl) imidazole to the silanised surface by means of non-covalent interactions.
- To characterise the modified material be X-ray photoelectron spectroscopy.
Our results will be presented in this communication.
REFERENCES
Ando, N., Terashima, S. (2010). A novel synthesis of the 2-amino-1H-imidazol-4- carbaldehyde derivatives and its application to the efficient synthesis of 2-aminoimidazole alkaloids, oroidin,hymenidin, dispacamide, monobromodispacamide, and ageladine Aq. Tetrahedron, 66, 6224-6237.
Ang, G., Ruiqiang , H., Chu, P. (2016). Recent advances in anti-infection surfaces fabricated on biomedical implants by plasma-based technology. Surf. Coat. Tech., 1-5.
Fung, S.-Y., Sofiyev, V., Schneiderman, J., Hirschfeld, A., Victor, R., Woods, K., de Voogd, N. (2014) Unbiased screening of marine sponge extracts for anti-inflammatory agent combined with chemical genomics identifies girolline as an inhibitor of protein synthesis. ACS Chem. Biol, 9(1), 247–257.
Mai, T., Tintillier, F., Lucasson, A., Moriou, C., Bonno, E., Petek, S., Magré, K., Al-Mourabit, A., Saulnier, D., Debitus, C. (2015) Quorum sensing inhibitors from Leucetta chagosensis Dendy, 1863. Lett. Appl. Microbiol.,61(4), 311-317.
Rautray, T., Narayanan, R., Kwon, T.-Y., Kim, K.-H. (2010) Review Surface Modification of Titanium and Titanium Alloys by Ion Implantation. J. Biomed. Mater. Res. B Appl. Biomater., 93(2), 581-591.
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