Selenium-based amorphous semiconductors and their application in biomedicine

Selenium is a semimetallic and covalent nonoxide amorphous semiconductor lying in Group VI of the periodic table. Selenium-based amorphous semiconductors have always been known as robust and hard materials, being utilized as high temperature semiconductors for advanced applications. Selenium-based thin films have very high electron conductivity and can be used as an ideal conductive layer (electrical conductivity lying between 10−13 to 10−3Ω−1cm−1) for a number of devices in the biomedical field that require electrical interface for biologic applications. Selenium as a biomedical material, helping out some basic technology, is used in various medical systems and devices. It can be produced in solid noncrystalline, monocrystalline, and polycrystalline forms owing to its operating capability under high temperature and high bond strength. Selenium is an essential nutrient in biologic tissues and also possesses antibacterial properties. Selenium, among different varieties of nanoparticles, has attracted huge attention owing to properties like good absorbing capacity, ability to interact with protein, higher bioavailability, and low toxicity, and it has accorded wide applications in medical diagnostics and use of nanobiotechnology for biologic systems. Presently, selenium nanoparticles are reported to have biofilm inhibiting properties besides being antioxidant and anticancer agents. It is contained in the active center of many functional proteins and antioxidant enzymes, and it plays a crucial role in reducing oxidative body stress. It also helps in preventing a number of diseases such as diabetes, cancer, hypercholesterolemia, and various cardiovascular diseases. Though selenium is crucial for numerous metabolic processes, its excess beyond the required concentration in body leads to selenium toxicity. selenium nanoparticles, therefore, have widespread application in solar cells, xerography, photographic exposure meters, and rectifiers.