Protein Resistance of Polyurethane with Hydrophilic and Hydrophobic Soft Segments

Polyurethane (PU) containing poly(propylene glycol) (PPG) or poly(tetramethylene oxide) (PTMG) soft segments have been prepared by two-step condensation polymerization. The former (PPG-PU) with a lower critical solution temperature (LCST) at 21 C can change from hydrophilic to hydrophobic, whereas the latter (PTMG-PU) is hydrophobic at a temperature above 0 C. The adsorption of fibrinogen, bovine serum albumin, or lysozyme on such a PU surface in aqueous solution has been investigated by use of quartz crystal microbalance with dissipation (QCM-D) and surface plasmon resonance (SPR) in real time. PPG-PU surface exhibits protein resistance at a temperature below the LCST of PPG, but it significantly adsorbs proteins at a temperature above the LCST. On the other hand, the hydrophobic PTMG-PU surface adsorb the proteins at any temperatures investigated, in contrast with the hydrated poly(ethylene glycol) exhibiting excellent protein resistance. The hydration and dehydration of the polymers at different temperatures were confirmed by Raman spectroscopy. Our study demonstrates that the protein resistance of polymers is determined by their hydration. (C) 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 1987-1993, 2010