Study on physisorption between G-actin and amphiphilic polymer-coated gold nanoparticles.

Physisorptions occurs everywhere and constantly in living organisms and between nanomaterials and biomolecules. In this study, one of the most important proteins, G-actin, was selected to investigate its bio-nano physisorption with a model nanoparticle coated with a amphiphilic polymer. Using a photoluminescence quenching method, both the binding constant and the Hill constant were determined as 1.79 × 107  M-1 and 0.84, respectively. Thermodynamic calculations proved that such a physisorption was a spontaneous procedure. The physisorption-mediated protein-nanoparticle conjugates were robust enough to resist gel electrophoresis, and protein conformation was kept intact, as revealed using circular dichroism. This conjugate might be a promising candidate for nanofabrication or could play a significant role in actin-related bioactivities.