Interaction of porcine gastric mucin (PGM) with rigid nanoparticles (NPs) in neutral aqueous solution and its impact on the lubricating properties of PGM

Abstract

Porcine gastric mucin (PGM) is an attractive material as hydrophilic and slippery coatings for hydrophobic surfaces in a broad range of engineering applications. As inspired from effectiveness of a number of polycations as crosslinker between PGM molecules, leading to a remarkable enhancement of slipperiness of PGM coatings, feasibility of various rigid nanoparticles (NPs) as crosslinking agent with PGM has been explored in this study. Control experiments involving metal cations have shown that an aggregation of PGM molecules occurred upon interaction with multivalent cations, e.g. Fe3+, but no appreciable improvement in boundary lubricating properties of PGM was observed. Three different types of NPs varying in surface chemistry and size have shown that rigid NPs do not function as complexing agent between PGM molecules nor induce a significant synergistic improvement in the boundary lubricating properties of PGM. This study, however, indirectly implies that flexibility and charge density may be two important factors for polycations to function as complexing agents with PGM.