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Russian-German Forum on Nanotechnology
22-23 May 2013
Tomsk, Russia
Plenary lecture
Ass. Prof. Dr. Roman Surmenev
Theoretical and Experimental Physics Department
National Research Tomsk Polytechnic University, Russia
634050, Lenin av. 30, Tomsk, Russia
E-mail: [email protected]
Tel. +7 903 953 09 69
The physicochemical properties of silicate- or silver-containing hydroxyapatite coatings
on medical implant surfaces
A. Sharonova1, M. Surmeneva1, V. Pichugin1, A. Ivanova1, I. Grubova1, O. Prymak2,
M. Epple2, and R. Surmenev1
1
Department of Theoretical and Experimental Physics, Tomsk Polytechnic University,
634050 Tomsk, Russia
2
Inorganic Chemistry and Center for Nanointegration Duisburg-Essen (CeNIDE), University
of Duisburg-Essen, 45117 Essen, Germany
Hydroxyapatite (HA, Ca10(PO4)6(OH)2) coatings modified with either silica (Si-HA) or silver (Ag-HA) have
been deposited by means of RF-magnetron sputtering (RF) at a power of 30-290 W, a negative substrate
bias up to 100 V, and a pressure of 0.1 Pa. Technically pure titanium, silicon (111) single crystals, and
potassium bromide (KBr) single crystals were used as substrates. As-deposited thin calcium phosphate
(CaP) coatings (up to 1 m thick) were characterized by EDX, ESEM, XRD, TEM, IR spectroscopy, and
scratch-test. The biological response to the studied films have been carried out using in vitro tests. For
instance, the cell viability was evaluated by the MTT assay using MG-63 osteoblast-like sarcoma cells.
This test is based on the ability of living cells to reduce tetrazolium dye MTT to purple formazan crystals.
In the case of Ag-HA coatings, antibacterial studies were performed in vitro by means of inhibition zone
test using Escherichia coli (E. Coli) bacteria. As-deposited CaP-based coatings were dense and pore-free,
and their composition was close to that of the precursor target composition. The chemical and phase
composition as well as thickness and structure can be varied by adjusting the deposition control
parameters. A low rf-power density (0.1-0.5 W cm-2) resulted in amorphous or low crystalline CaP-coating
structure, and an increase in rf-power level (>0.5 W cm-2) induced the crystallization of the coating. The
diffraction patterns of the coatings corresponding to crystalline HA. The four strongest peaks were
observed at 25.8° (002), 31.7° (211), 32.2° (112), and 32.9° (300) (Cu Kα radiation; 1.54 Å). The (002)
peak dominated the diffraction pattern, indicating a preferred c-axis crystallographic orientation. Its
intensity increased with film thickness. With an increase in the substrate bias voltage from 0 to −100 V, the
intensity of the (002) peak gradually decreased. The MTT test revealed that the cell viability on Si-HA
coated surfaces was up to 70% higher than that in case of control substrates. On the surface of the
coatings, cells with a spread-out morphology were observed. Therefore, in vitro cell culture results
demonstrated that osteoblast-like cells attached and proliferated well on the surface of the coatings. No
significant antibacterial effect was found in the case Ag-HA coatings. Based on the obtained results it can
be concluded that RF allowed us to prepare CaP-based coatings with different structure and stoichiometry
controlling the deposition parameters.
Ass. Prof. Dr. Roman Surmenev, National Research Tomsk Polytechnic University
1