Enterprise Europe Network

Ligand-free production of gold nanoparticles

Country of origin:
External Id: 
Last update
Expiration date


Partner keyword: 
Inorganic Chemistry
Organic Chemistry
Micro- and Nanotechnology
Micro- and Nanotechnology related to Biological sciences
Pharmaceuticals/fine chemicals
Speciality metals (including processes for working with metals)
Speciality/performance chemicals
Other research and experimental development on natural sciences and engineering


A German university has developed a process for the production of ligand-free gold nanoparticles. These gold particles show new physical and chemical properties and allow a quantitative production. The university offers a license agreement to partners from the chemical or pharmaceutical industry.



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 (ΓΈ 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.

Advantages & innovations

Cooperation plus value: 
The process described here only uses ligands that contain oxygen and hydrogen and either escape into the air as oxygen or disintegrate into water. They therefore no longer have the disturbing properties. Au-NPs with a size of about 3nm show a sudden change in the physical properties and thus also in the chemical properties in comparison to larger particles. Ligand- free gold nanoparticles have recently been at the center of intense research, addressing a diverse market. The present invention gives access to large quantities.

Stage of development

Cooperation stage dev stage: 
Prototype available for demonstration

Partner sought

Cooperation area: 
The university offers access to rights for commercial use as well as the opportunity for further co-development within a license agreement to companies from the pharmaceutical or chemical sector. Possible applications are in the field of heterogeneous and homogeneous catalysis as well as in biomedical and physical applications (e.g. electroluminescence). A potential partner would have to convert the process from the university laboratory into real production. The university offers support with the implementation.


Particle size distribution cluster