IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Biomaterials Tuesday Sessions
       Session BI-TuA

Paper BI-TuA5
Novel PEO-containing Copolymers as Protein Repellent Additives In Polyurethanes: Evaluation of Protein Interactions by Radiolabelling, XPS and MALDI

Tuesday, October 30, 2001, 3:20 pm, Room 102

Session: Non Fouling Surfaces and Theoretical Concepts
Presenter: K.M. McLean, CSIRO Molecular Science, Australia
Authors: J.H. Tan, McMaster University, Canada
K.M. McLean, CSIRO Molecular Science, Australia
T.R. Gengenbach, CSIRO Molecular Science, Australia
H.J. Griesser, CSIRO Molecular Science, Australia
J.L. Brash, McMaster University, Canada
Correspondent: Click to Email
Polyurethanes (PUs) have long been used for medical applications, mainly because of their excellent mechanical properties. However, there is a need to improve the biocompatibility of these materials. Polyethylene oxide (PEO) has gained recognition as a biocompatible material and appears to interact minimally with proteins and cells. In this work, materials have been developed based on PEO-containing additives that can be applied to conventional PUs. The additives are amphiphilic triblock copolymers, PEO-PU-PEO, the middle segment of which has the same structure as the PU substrate. We hypothesize that such additives should interact strongly and be compatible with any polyurethane of structure similar to the middle segment, and that they should migrate to the PU-aqueous interface. Copolymers were synthesized using PEO blocks of varying MW (550, 2000, 5000) and a central PU block of MW 5000. Materials were prepared by blending the block copolymers with a base PU. The surfaces were characterized by water contact angle and XPS. Adsorption of proteins was investigated by radiolabelling and by XPS. The water contact angle data showed that the blends became more hydrophilic with increasing copolymer content. Radiolabelled fibrinogen expts showed that adsorption was much lower on the blends than on the unmodified PU, in some cases showing reductions of greater than 99%. For the 10% blends, surprisingly, adsorption decreased in the order PEO5000>2000>550. This "inverse dependence" is attributed to slower diffusion of the higher MW copolymers to the interface. The protein adsorption characteristics were also investigated using XPS and surface-MALDI using a range of individual plasma proteins (fibronectin, vitronectin, albumin, insulin, fibrinogen and IgG) and whole plasma. XPS results confirmed that protein adsorption on the blends was negligible compared to the unmodified PU. Ongoing surface MALDI experiments also indicate low adsorption on the copolymer-PU blends.