Preparation and characterisation of novel, blood-plasma-separation membranes for use in biosensors

Permeability and selectivity are important membrane properties in terms of the performance of membranes. In practice, more superior membrane selectivi ty often means poorer permeability and vice-versa. This is particularly tru e for membranes designed for the isolation of highly deformable materials f rom aqueous-based fluids. Separation of red blood cells from whole blood is a typical example of this kind. This paper concerns the development of mem branes for the separation of highly deformable red blood cells from whole b lood samples, for use in biosensor assemblies. The formulations of these me mbranes were designed as such that the membranes responded to blood samples and took several steps to achieve efficient separation of the red blood ce lls from blood, whilst allowing efficient transport of plasma through the m embrane. Thus, the membranes consisted of, at least, one water-insoluble po lymer, one partly water-soluble polymer and one polymer that enhanced the f ormation of rouleaux of red blood cells. The structure of the membranes was controlled by carefully designed formulation of the polymer solution used in casting the membrane and the casting conditions. Each membrane component interacted with various components in the blood in a desired sequence. As a result, thorough separation of red blood cells from blood was achieved at relatively low mechanical driving force. (C) 2000 Elsevier Science B.V. Al l rights reserved.