DEVELOPMENT OF A HEMOCOMPATIBLE PO(2) SENSOR WITH PHOSPHOLIPID-BASED COPOLYMER MEMBRANE

This paper describes research to improve the haemocompatibility of an intravascular pO(2) sensor utilizing a novel copolymer membrane. This material is based on a methacrylate monomer having an electrically neu tral head group, 2-methacryloyloxyethyl phosphorylcholine (MPC), copol ymerized with n-butyl methacrylate (BMA). The MPC mimics the outer lay er lipid structure of the red blood cell membrane, and thus poly (MPC- co-BMA) could be expected to show excellent compatibility with blood. In this paper the methods of preparation of a pO(2) sensor covered wit h different types of membrane, including polyetherurethane (PU), polyv inyl chloride (PVC), poly (MPC-co-BMA) and a compound membrane [PVC+po ly (MPC-co-BMA)] are described. The surface chemical structure of the different types of membrane were characterized with Fourier transform infrared spectroscopy. Scanning electron microscopy was used to examin e the surface contamination after the sensors had been used in blood. The properties of the sensors were first assessed in phosphate-buffere d solution, and the short-term and long-term performances were then de monstrated by use of buffer with mixed proteins, serum and whole human blood. The sensors coated with poly (MPC-co-BMA) and PVC+poly (MPC-co -BMA) membranes showed stable behaviour in static human blood, whereas the sensors with PU and PVC membrane were subject to a continuous sig nal deterioration during the test period. (C) 1996 Elsevier Science Li mited.