Nanobiotechnology for health-care

Influence of temperature factor on the properties of silver nanoparticles and their bio-activity in vitro
Lytvyn S.Ye.1, Kurapov Yu.A.1, Ruban N.M.2, Didikin G.G.1, 
Boretskii V.V.1, Churkina L. N. 3
1 E. O. Paton Electric Welding Institute of the NAS of Ukraine, Kazymyr Malevych, 11, Kyiv- 03150, Ukraine
E-mail: litvin@paton.kiev.ua
2 L. V. Gromashevskii Institute of Epidemiology and Infectious Diseases of the NAMS of Ukraine, Amosov, 5, Kyiv-03038, Ukraine
3 Danylo Zabolotny Institute of Microbiology and Virology of the NAS of Ukraine, Acad. Zabolotny, 154, Kyiv-03680, Ukraine

Physical synthesis of silver NPs by the method of condensation of mixed molecular flows in vacuum allows obtaining nanostructured material in the form of a dry substance (silver NPs in a water-soluble matrix), which allows preserving, storing and transporting the nanoparticles. 
Low thermodynamic stability of silver compounds with oxygen did not allow directly identifying them by the methods of TEM and X-Ray Diffraction, although the method of thermogravimetric analysis registered the transformation processes in Ag-O system. Probably, silver NPs have on their surface a very thin film of silver oxide in the form of an Ag2O phase [1], then it decomposes at a temperature of 430 °С.
It was found that the minimum inhibitory concentration of silver nanosolution, which researched the growth of the studied S.aureus strains was 10 mg/l.
Preparations with silver nanoparticles, both the initial sample and the samples obtained at different annealing temperatures (200 °C, 400 °C, 650 °C) at concentrations of 10.0 and 20.0 mg/l, have a bactericidal effect on S.aureus strains after 24 hours of exposure. However, at concentration of 5 mg/l, bacteriostatic effect on staphylococci of these high temperature preparations is observed with the exception of the original.

1.	Roy R., Hoover M. R., Bhalla A. S., Slawecki T., Dey S., Cao W., Li J., Bhaskar S. Ultradilute Ag-aquasols with extraordinary bactericidal properties: role of the system Ag–O–H2O // Mat. Res. Innovations.-2007.-11, N1.-P. 3–18.