Nanobiotechnology for health-care 

Biological activity of metal nanoparticles as basis for development of bio- and nanosensors  
Dybkova K.M.1,2, Rieznichenko L.S.2, Gruzina T.G.2, Dybkova S.M.2
1 Biology and Medicine Institute Science Educational Center of Taras Shevchenko National University of Kyiv, Glushkova Av., 2, Kyiv-02000, Ukraine. 
E-mail: kateryna.dybkova@gmail.com
2 Department of Colloidal Technologies of Natural Systems, F.D. Ovcharenko Institute of Biocolloidal Chemistry NAS of Ukraine, Vernadskogo Av., 42, Kyiv-03142, Ukraine.

Nanomaterials, especially metal nanoparticles, are actively used today in the creation of modern bio- and nanosensors for the detection of pathogens, toxins, pollutants, blood markers etc. The use of nanomaterials usually is limited by their physicochemical properties (surface plasmon resonance, electrical conductivity, magnetic properties etc.). At the same time, high biological activity of certain metal nanoparticles can be the basis for development and improvement of the diverse bio- and nanosensors.
The peculiarities of contact interaction of the synthesized gold (AuNP), silver, iron nanoparticles with enzymes and bacterial cells were studied. It was revealed strong dependence of these processes from the nature, size and concentration of the nanoparticles. For example, short-term incubation (3-5 min) of the glucose oxidase with spherical AuNP (d=30 nm) at a concentration of 0.386 μg metal / mg enzyme and 0.048 μg metal / mg enzyme led to stimulation of the enzymatic activity by 56% and 95% respectively, whereas the enzymatic activity remained at the control level under the influence of the same AuNP at the other investigated concentrations. The concentration 0.386 μg of metal / mg of enzyme for 30 nm spherical AuNP was also the optimal to form the electroactive complex of the enzyme with nanoparticles (according to the data of electrophoretic mobility). Received peculiarities can be used for improvement the immobilization of enzymes on the electrode and amplification of the electrochemical signals in the process of the electrochemical bio- and nanosensors development. 
Based on the revealed peculiarities of the synthesized gold, silver and iron nanoparticles interaction with bacteria cells the prospects to their use in the development of the optical nanosensors for the detection of pathogenic bacteria have been demonstrated. The response time when using the synthesized nanoparticles exceeds the control method by 5-6 times, the sensitivity of the determination is 1x103 CFU/ml.