10.1021/la202586j.s001 David Cozzens David Cozzens Arnold Luk Arnold Luk Umaprasana Ojha Umaprasana Ojha Marina Ruths Marina Ruths Rudolf Faust Rudolf Faust Surface Characterization and Protein Interactions of Segmented Polyisobutylene-Based Thermoplastic Polyurethanes American Chemical Society 2011 Competitive adsorption experiments HSA PIB platelet receptor ligand PTMO AFM contact angle measurements polyether TPUs quartz crystal microbalance surface 2011-12-06 00:00:00 Journal contribution https://acs.figshare.com/articles/journal_contribution/Surface_Characterization_and_Protein_Interactions_of_Segmented_Polyisobutylene_Based_Thermoplastic_Polyurethanes/2574925 The surface properties and biocompatibility of a class of thermoplastic polyurethanes (TPUs) with applications in blood-contacting medical devices have been studied. Thin films of commercial TPUs and novel polyisobutylene (PIB)–poly(tetramethylene oxide) (PTMO) TPUs were characterized by contact angle measurements, X-ray photoelectron spectroscopy, and atomic force microscopy (AFM) imaging. PIB-PTMO TPU surfaces have significantly higher C/N ratios and lower amounts of oxygen than the theoretical bulk composition, which is attributed to surface enrichment of PIB. Greater differences in the C/N ratios were observed with the softer compositions due to their higher relative amounts of PIB. The contact angles were higher on PIB-PTMO TPUs than on commercial polyether TPUs, indicating lower surface energy. AFM imaging showed phase separation and increasing domain sizes with increasing hard segment content. The biocompatibility was investigated by quantifying the adsorption of fouling and passivating proteins, fibrinogen (Fg) and human serum albumin (HSA) respectively, onto thin TPU films spin coated onto the electrode of a quartz crystal microbalance with dissipation monitoring (QCM-D). Competitive adsorption experiments were performed with a mixture of Fg and albumin in physiological ratio followed by binding of GPIIb-IIIa, the platelet receptor ligand that selectively binds to Fg. The QCM-D results indicate similar adsorbed amounts of both Fg and HSA on PIB-PTMO TPUs and commercial TPUs. The strength of the protein interactions with the various TPU surfaces measured with AFM (colloidal probe) was similar among the various TPUs. These results suggest excellent biocompatibility of these novel PIB-PTMO TPUs, similar to that of polyether TPUs.