Exploring gold nanoparticles interaction with mucins: A spectroscopic-based study.

The interaction between two mucin types (mucin from porcine stomach - PGM and mucin from bovine submaxillary glands - BSM) and gold nanoparticles (GNPs) of various size (5, 20 and 40 nm) and functionalization (with cysteamine or thioglycolic acid) was studied under physiological conditions, in order to investigate the affinity of the nanoparticles to the proteins. Different methods are employed to monitor the interactions: UV-vis and fluorescence spectroscopy, fluorescence lifetime, circular dichroism and transmission electron microscopy. These studies have shown the formation of a complex between GNPs and both PGM and BSM. This aspect could be of great importance for the use of gold nanoparticles for biomedical purposes in those diseases where qualitative and quantitative mucin anomalies play an essential role in mucus composition and rheology.