Aggregation and Adsorption of Type I Collagen near an Electrified Interface

An electric field can stimulate collagen fibrillogenesis in an acidic electrolyte, while unaggregated collagen monomers are preferentially adsorbed to the electrified interface itself. These effects are demonstrated using a Hull cell to apply an electric current gradient to 0.01 M HCl or 0.01 M HNO3 containing collagen monomers. Atomic force microscopy and Raman scattering spectroscopy data show that collagen microfibrils form in the electrolyte and migrate toward the negatively charged working electrode. However, collagen monomers adsorb to the working electrode due in part to their faster electromigration rates. Despite the dramatic pH difference between the acidic bulk electrolyte (pH = 2) and the basic diffusion layer region in the immediate vicinity of the working electrode surface (pH > 10) due to base electrogeneration reactions in the aqueous electrolytes, there is no evidence that the electroadsorbed collagen monomers suffer from the effects of denaturation.