April 10, 2006
“Green” Method Developed For Making Gold Nanoparticles
Turning to a unique class of liquids known as ionic solvents, researchers at the Korea Advanced Institute of Science and Technology, in Daejeon, have developed a simple, far less polluting method of producing pure metal nanoparticles for use in biomedical applications. This new method is reported in the Journal of Materials Chemistry.
Huen Lee, Ph.D., led the team in its efforts to develop a water-phase synthesis of gold nanoparticles using what are called alcohol ionic liquids. Lee and his colleagues regarded ionic liquids as potentially useful for making metal nanoparticles because of the ability of these type of fluids to both stabilize and facilitate the transfer of electrons to metal ions. Such electron transfer is crucial to the formation of metal nanoparticles from metal ions dissolved in a solvent.
Preparing gold nanoparticles using ionic liquids is straightforward. Metal salts are first dissolved in the ionic liquid. The resulting solution is then added to water, triggering a chemical reaction that adds electrons to the metal ions and triggers the formation of gold nanoparticles. The final particle size is controlled by the makeup of the ionic liquid, providing an easy way to fine-tune the physical characteristics of the nanoparticles. The nanoparticles produced using this method are uniform in size and shape.
Besides providing a simple and relatively inexpensive method for making nanoparticles from gold and other metals, the new technique also eliminates the need to use organic solvents and other potentially toxic chemicals during nanoparticle synthesis. Reducing the use of such materials stands to drive down the cost of producing metal nanoparticles by eliminating the need to recover and dispose of these materials in a safe and environmentally responsible manner.
This work is detailed in a paper titled, “Facile one-pot synthesis of gold nanoparticles using alcohol ionic liquids.” An abstract of this paper is available at the journal’s website.