Please have a look at the following artcles which might be helpful for you

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2626931/

http://download.springer.com/static/pdf/112/art%253A10.1186%252Fs12951-014-0028-6.pdf?originUrl=http%3A%2F%2Flink.springer.com%2Farticle%2F10.1186%2Fs12951-014-0028-6&token2=exp=1457103502~acl=%2Fstatic%2Fpdf%2F112%2Fart%25253A10.1186%25252Fs12951-014-0028-6.pdf%3ForiginUrl%3Dhttp%253A%252F%252Flink.springer.com%252Farticle%252F10.1186%252Fs12951-014-0028-6*~hmac=1fec85c2ed2fc1a76a045dd77916c9de036c57e95cbaabe36f7571adb5161945

Maybe you can see the Se useful to think about nano Se useful.

The largest commercial use of Se, accounting for about 50% of consumption, is for the production of glass. Se compounds confer a red color to glass. Selenium is used with bismuth in brasses to replace more toxic lead.

The chief commercial uses for selenium today are in glassmaking and in pigments. Selenium is a semiconductor and is used in photocells. Uses in electronics, once important, have been mostly supplanted by silicon semiconductor devices. Selenium continues to be used in a few types of DC power surge protectors and one type of fluorescent quantum dot.

Selenium in biology.

The amino acid selenocysteine is a common form of selenium in biology.

You might see some informations from the following paper:

Effects of Dietary Nano-Selenium on Tissue Selenium Deposition, Antioxidant Status and Immune Functions in Layer Chicks

http://scialert.net/fulltext/?doi=ijp.2014.160.167

Dear colleagues; Prof. Agrawal and Prof. Chen.

Thank you very much for your kind assistance. I wish all good.

Hi Mr. Khaled. Biogenic Se NPs have advantages and wide applicability in the field of nanomedicine such as antimicrobial, antioxidant and anticancer agent. They have also been reported to be employed on electrochemical nanobiosensors for detection of hydrogen peroxide as well as wastewater treatment in terms of their environmental application.

Dear Prof. Fatemeh Soroodi

Thank you very much for your valuable assistance.

Best wishes and regards