title: Transport-Limited Adsorption of Plasma Proteins on Bimodal Amphiphilic Polymer Co-Networks: Real-Time Studies by Spectroscopic Ellipsometry.
abstract: Traditional hydrogels are commonly limited by poor mechanical properties and low oxygen permeability. Bimodal amphiphilic co-networks (β-APCNs) are a new class of materials that can overcome these limitations by combining hydrophilic and hydrophobic polymer chains within a network of co-continuous morphology. Applications that can benefit from these improved properties include therapeutic contact lenses, enzymatic catalysis supports, and immunoisolation membranes. The continuous hydrophobic phase could potentially increase the adsorption of plasma proteins in blood-contacting medical applications and compromise in vivo material performance, so it is critical to understand the surface characteristics of β-APCNs and adsorption of plasma proteins on β-APCNs. From real-time spectroscopic visible (Vis) ellipsometry measurements, plasma protein adsorption on β-APCNs is shown to be transport-limited. The adsorption of proteins on the β-APCNs is a multistep process with adsorption to the hydrophilic surface initially, followed by diffusion into the material to the internal hydrophilic/hydrophobic interfaces. Increasing the cross-linking of the PDMS phase reduced the protein intake by limiting the transport of large proteins. Moreover, the internalization of the proteins is confirmed by the difference between the surface-adsorbed protein layer determined from XPS and bulk thickness change from Vis ellipsometry, which can differ up to 20-fold. Desorption kinetics depend on the adsorption history with rapid desorption for slow adsorption rates (i.e., slow-diffusing proteins within the network), whereas proteins with fast adsorption kinetics do not readily desorb. This behavior can be directly related to the ability of the protein to spread or reorient, which affects the binding energy required to bind to the internal hydrophobic interfaces.
authors.affiliation: Polymer Engineering Department, The University of Akron , Akron, Ohio 44325, United States.
authors.forename: Gustavo
authors.initials: G
authors.lastname: Guzman
authors.affiliation: Polymer Engineering Department, The University of Akron , Akron, Ohio 44325, United States.
authors.forename: Sarang M
authors.initials: SM
authors.lastname: Bhaway
authors.affiliation: Chemistry Department, Polymer Research Center, Boğaziçi University , Bebek, 34342 Istanbul, Turkey.
authors.forename: Turgut
authors.initials: T
authors.lastname: Nugay
authors.affiliation: Polymer Engineering Department, The University of Akron , Akron, Ohio 44325, United States.
authors.forename: Bryan D
authors.identifier: 0000-0003-1916-7145
authors.initials: BD
authors.lastname: Vogt
authors.affiliation: Polymer Engineering Department, The University of Akron , Akron, Ohio 44325, United States.
authors.forename: Mukerrem
authors.identifier: 0000-0001-9128-7833
authors.initials: M
authors.lastname: Cakmak
mesh_terms: D000327:Adsorption; D001798:Blood Proteins / Q000737:chemistry*; D057927:Hydrophobic and Hydrophilic Interactions; D007700:Kinetics; D011108:Polymers / Q000737:chemistry*; D013499:Surface Properties
chemical_list: D001798:Blood Proteins; D011108:Polymers