Nanobiotechnology for health-care

The role of pluronic F68 in AgAu/tryptophan system for stability and toxicity of bimetallic nanoparticles
Iu. Mukha1, N. Vityuk1, G. Grodzyuk2,3, M. Skoryk3,4 A. Lyberopoulou5, 
H. Katifelis5, M. Gazouli5
1 Chuiko Institute of Surface Chemistry, NAS of Ukraine, Kyiv, Ukraine.    E-mail: iu.mukha@gmail.com
2 Pisarzhevskii Institute of the Physical Chemistry, NAS of Ukraine, Kyiv, Ukraine. 3 NanoMedTeсh LLC, Kyiv, Ukraine.
4 Kurdyumov Institute for Metal Physics, NAS of Ukraine, Kyiv, Ukraine.
5 Laboratory of Biology, Medical School, National and Kapodistrian University of Athens, Athens, Greece

The use of amino acid tryptophan for silver/gold nanoparticles (NPs) preparation is a promising way to decrease the toxicity of nanosized noble metals. Acting as a reducing agent of metal ions and a particle stabilizer tryptophan resulted in stable metal colloid with anticancer effect [1,2]. For the successful medical examination of Ag/Au NPs effect, especially during in vivo experiments, highly concentrated metal colloids are required, and their preparing remains a problem. 
In this study we developed synthetic procedure to increase metal concentration in colloid without loss of NPs stability and nanodimension of particles. For this purpose we used polymer pluronic F68. It allowed to increase the concentration of metals up to CAu = 4x10-3 M, that corresponded for example to 0,8 mg/ml of gold. At such high concentrations of metal colloids are very dark liquids, almost indistinguishable by color for different metal composition. But specific absorption bands of localized surface plasmon resonance of metals appeared after dilution of colloids having typical position for bimetallic Ag/Au nanoparticles, located between 415 and 528 nm. Furthermore, in order to test the cytotoxicity of bimetallic NPs we performed MTT assay in various cancer cell lines and non-cancer cell lines. From the study, it is outlined that pluronic F68 Ag/Au/tryptophan system execs advanced toxicity in cancer cells versus non-cancer cells (HEK293), in which the toxicity is found significantly reduced. 

1.	Iu. Mukha, N. Vityuk, G. Grodzyuk, S. Shcherbakov, A. Lyberopoulou, E.P. Efstathopoulos, M. Gazouli Anticancer effect of Ag, Au, and Ag/Au bimetallic nanoparticles prepared in the presence of tryptophan // J Nanosci Nanotechnol.-2017.-17, 12.-P.8987-8994.
2.	I. Shmarakov, Iu. Mukha, N. Vityuk, V. Borschovetska, N. Zhyshchynska, G. Grodzyuk, A. Eremenko Antitumor Activity of Alloy and Core-Shell-Type Bimetallic AgAu Nanoparticles // Nanoscale Res Let.-2017.-12.-P.333.