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 selectivity often means poorer permeability and vice-versa. This is particularly true for membranes designed for the isolation of highly deformable materials from aqueous-based fluids. Separation of red blood cells from whole blood is a typical example of this kind. This paper concerns the development of membranes for the separation of highly deformable red blood cells from whole blood samples, for use in biosensor assemblies. The formulations of these membranes were designed as such that the membranes responded to blood samples and took several steps to achieve efficient separation of the red blood cells from blood, whilst allowing efficient transport of plasma through the membrane. Thus, the membranes consisted of, at least, one water-insoluble polymer, one partly water-soluble polymer and one polymer that enhanced the formation 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.