Importance of gold nanoparticles for detection of toxic heavy metal ions and vital role in biomedical applications

In the last few decades gold nanoparticles have become an intense topic of research due to it's eminent size and morphology dependent optical, chemical, physical and electrical properties. Gold nanoparticles show useful technological applications in the province of nanoelectronics, optoelectronics, chemical and biological sensors. Due to the size- and shape-dependent properties, synthesis of gold nanoparticles with various methods is still an important area of research.Recent literature reports indicate that gold nanoparticles have vast biomedical applications such as biosensors, bio-imaging, targeted drug delivery and controlled drug release. Other than size and shape, the inter-particle distance dependent optical properties of gold nanoparticles have very interesting applications in the field of sensors. Gold nanoparticles show good selectivity and sensitivity for colorimetric identification of heavy toxic metal ions such as Hg2+, Cd2+, As3+, Pb2+ etc and various biomolecules. The concentration of such toxic metal ions in water can be identified by naked eye also.