Evaluation of the permeability and blood-compatibility properties of membranes formed by physical interpenetration of chitosan with PEO/PPO/PEO triblock copolymers

In order to develop blood compatible membranes with controlled porosity, we have fabricated and examined the properties of physical interpenetrating network (PIN) of chitosan and poly(ethylene oxide)/poly(propylene oxide)/poly(ethylene oxide) (PEO/PPO/PEO) triblock copolymers (Pluronics(R)). Degree of equilibrium swelling, scanning electron microscopy, and electron spectroscopy for chemical analysis (ESCA) were used to characterize the bulk and surface properties. Vitamin B(12) and human serum albumin were used as permeability markers. Platelet adhesion and activation were used to determine the blood-interaction properties of the PIN membranes. Unlike chitosan membranes that were nonporous, the chitosan-Pluronic PIN membranes were highly porous with the pore size, depending on the type of incorporated Pluronic polyol. ESCA results showed a significant increase in the -(C) under bar -O- signal of C1s spectra on the PIN membranes that correlates with the presence of PEO chains on the surface. The permeability coefficients of vitamin B(12) and albumin were higher in the chitosan-Pluronic PIN membranes than in the control. The number of adherent platelets and the extent of activation were significantly reduced on the chitosan-Pluronic PIN membranes. The decrease in platelet adhesion and activation correlated positively with the PEO chain length of the incorporated Pluronic polyols. The results of this study show that chitosan-Pluronic PIN membranes offer a blood-compatible alternative with a higher-molecular-weight cutoff for use in hemodialysis and related applications. (C) 2001 John Wiley & Sons, Inc.