Question: Does it cost you a lot to attach molecules to the tiny gold nanoparticles? Surely gold is expensive?

Nicola Rogers answered on 8 Mar 2014:

gold is quite expensive, but nanoparticles are incredibly small so we don’t use very much! The gold nanoparticles are ‘dissolved’ in water and are quite dilute as well. However, the luminescent molecule that I attach to the gold nanoparticles is infact more expensive than the nanoparticles because it contains ruthenium metal, which is also expensive. In addition= to make the ruthenium luminescent compound the reaction has 5 steps – so it takes a couple of weeks to make the compound – and every time you finish a step you do lose some compound whilst trying to clean up the final product.