Effect of amount of hydrated water and mobility of hydrated poly(2-methoxyethyl acrylate) on denaturation of adsorbed fibrinogen

In this study, a blood-compatible polymer, poly(2-methoxyethyl acrylate) (PMEA), was grafted onto a gold substrate with various grafting densities (σ) (σ = 0–0.18 chains nm⁻²), and the amount of hydrated water and mobility of the polymer chain interacting with water molecules were quantitatively evaluated using a quartz crystal microbalance with an admittance system. The amount of hydrated water decreased with increasing σ. By contrast, the mobility of the hydrated PMEA was maximum at σ ≈ 0.12 chains nm⁻², revealing that the amount of high-mobility water at σ = 0.12 was higher than that at other densities. The degree of denaturation of the adsorbed fibrinogen was evaluated based on the hydrodynamic water ratio and viscoelasticity, and was found to increase with increasing σ. The denaturation of adsorbed fibrinogen was suppressed when both the amount of hydrated water and the mobility of hydrated PMEA were high. This study demonstrates that the interfacial state of the polymer chains hydrated in water is important for blood compatibility.