Biologically synthesized nanoparticles

The pH value of dialyzed solutions was within the 7.0-7.4 range that corresponds to the normal pH of biological systems. Taking into account that the average thickness of cell membranes is about 8-10 nm, we can suppose that the synthesized nanoparticles ( 2 nm) can penetrate through the cell membranes. The particles can be used in native, solubilized and modified forms. The senthisyzed nanoparticles were tested on the rat hepatocyte cells using the standard procedure of trypan blue dye exclusion [7]. For a particle concentration up to 50 mg/1, the toxic effect has not been detected. 

Karuppaiya, P., Satheeshkumar, E., Chao, W.T., Kao, L.Y., Chen, E.C., Tsay, H.S., 2013. Anti-metastatic activity of biologically synthesized gold nanoparticles on hiunan fibrosarcoma cell line HT-1080. Colloids Surf. B Biointerfaces 110, 163—170. 

Another field recently opened is the use of water-in-oil (W/O) microemulsions as reaction media for the synthesis of solid nanoparticles. The interest in synthesizing nanoparticles in solutions of reversed micelles is due to their important technological applications as catalysts for redox reactions [69] or their use to model or mimic processes occurring in geological or biological environments [70],... 

Morphology of Biologically Synthesized Precious Metal Nanoparticles 471... 

As mentioned earlier, biological systems have developed optimized strategies to design materials with elaborate nanostructures [6]. A straightforward approach to obtaining nanoparticles with controlled size and organization should therefore rely on so-called biomimetic syntheses where one aims to reproduce in vitro the natural processes of biomineralization. In this context, a first possibility is to extract and analyze the biological (macro)-molecules that are involved in these processes and to use them as templates for the formation of the same materials. Such an approach has been widely developed for calcium carbonate biomimetic synthesis [13]. In the case of oxide nanomaterials, the most studied system so far is the silica shell formed by diatoms [14]. 

It is also possible to synthesize metallic nanopartides with k- and i-carrageenan [59]. Both Ag and Au nanoparticles have considerable potential for biochemical analysis [60]. The advantage of Ag nanoparticles is that the range of dyes which remain effective in biological media is much more extensive. On the other hand, in some biological systems, such as cell suspensions, Ag can react positively with the cell and it is well know as a bactericide. Au, Ag and Cu nanoparticles have the ability to... 

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