Dear Ghazal Shariat Panahi ,

You should use three controls: i) containing cells and media; ii) containing only media; and iii) containing nanoparticles in media. With this, you can identify the healthy growth of cells without nanoparticles and to determine the absorbance of both the culture media and the nanoparticles. In fact, you may find a wavelength within the proper range of the MTT labeling reagent in which the absorbance of both the culture media and the nanoparticles is almost negligible, and therefore perform the absorbance measurements in the absorbance plate reader at that particular wavelength.

Dear GHazel,

Selenium is an important essential element that interferes through seleno proteins in many physiological processes of the organism and affects the production and reproductive properties. By providing adequate supply of selenium in the diet, it is possible to effectively prevent health problems from its deficiency. Traditional supplements of selenium generally have a low degree of absorption and increased toxicity. Therefore, it is imperative to develop innovative systems as transporters of selenium compounds, which will raise the bioavailability of this element and allow its controlled release in the organism. The development of new NP systems for the transport of selenium in the organism, with the possibility of modifying physicochemical properties of the particles, greater stability in the gastrointestinal tract, and allowing controlled release of selenium, offers a significant dietary and therapeutic potential. Selenium in its nanoform appears to be the most appropriate for supplementation, especially in ruminants, in which traditionally used selenium compounds exhibit very low absorption in the digestive tract.For the synthesis of SeNPs, the selenious acid solution (aqueous solution of SeO2) is mixed with an aqueous solution of a polysaccharide, for example, chitosan , and ascorbic acid solution , which gradually transforms the initially colorless solution into a red color solution. Elemental SeNPs are coated with chitosan, and the result is encapsulated nano-selenium form. Nanoscale selenium has a very wide range of biomedical applications. Controlling is necessary here to maintain healthy growth of cells by media.

Ashish