Protein Resistance of Surfaces Prepared by Chemisorption of Monothiolated Poly(ethylene glycol) to Gold and Dendronization with Aliphatic Polyester Dendrons: Effect of Hydrophilic Dendrons

Protein adsorption to surfaces prepared by chemisorption of thiol-terminated poly(ethylene glycol) (HS-PEG650-OH) to gold-coated silicon wafers followed by functionalization of the terminal PEG OH groups with aliphatic polyester dendrons was investigated. Chemisorption of HS-PEG650-OH to the gold surfaces was carried out under cloud-point conditions to give a chain density of ∼3.7 chains/nm2, as calculated from AFM film thickness measurements. Dendronization of the PEG-functionalized surfaces with aliphatic polyester dendrons, generations 1−4, was achieved using divergent dendron growth. The hydrophilicity of the surfaces increased significantly with increasing dendron generation as shown by water contact angle data. The effect of the hydrophilic dendrons on protein adsorption from phosphate-buffered saline (PBS) and plasma are reported. Adsorption of both 125I-radiolabled fibrinogen and lysozyme onto the dendronized surfaces showed that protein adsorption increases upon introduction of dendrons to the PEG-functionalized surfaces. The similarity between fibrinogen and lysozyme adsorption suggests that resistance of the dendronized surfaces to proteins follows the same trend regardless of protein size.