Nanoparticles of elements can behave quite differently than larger particles of the same element. Gold, which is actually relatively inert, can become very reactive as nanoparticles or at least influence or accelerate reactions. It therefore serves as a catalyst in the chemical industry or as an indication and therapy for cancer.
Ligands are normally needed to prevent the individual gold particles from clumping together. If they do, they are no longer nano and therefore unusable. However, ligands normally contain molecules such as ammonium, which interfere with chemical applications or are harmful in medical applications.
A German university has now developed a process for the production of ligand-free gold nanoparticles (Au-NP). A laser fragmentation process makes it possible to produce carbon-free gold nanoparticles (Au-NPs) smaller than 5nm. For this purpose, gold nanoparticles are removed in a liquid medium. Afterwards the laser fragmentation is repeated in a free jet of liquid and addition of inorganic oxidizing agents, e.g. ozone or hydrogen peroxide. In this way, gold nanoparticles smaller than 5 nm (ø particle size at approx. 2.5 nm) can be produced.
In addition to the production of gold clusters, ligand-free gold nanocubes can also be produced using this process.
The university offers a license agreement to companies from the chemical or pharmaceutical industry interested in using the process.