Bioanalytical applications of polyion-sensitive electrodes

Recent developments in the design and bioanalytical applications of polyion -sensitive electrodes (PSEs) are reviewed. The general electrochemical prin ciples governing the potentiometric response of such polymer membrane-based devices are summarized and new directions for the use of these novel senso rs are detailed. These new directions include basic fundamental studies aim ed at determining the thermodynamics of polyion extraction into ion exchang er-doped polymeric membranes, new methods to quantitate the anticoagulant d rug heparin in whole blood via titrations with polycationic protamine, sele ctive assays of protease activities land inhibitors of such activities) usi ng natural and synthetic polyionic peptides as substrates, and novel homoge neous immunoassay schemes based on potentiometric polyion detection. (C) 19 99 Elsevier Science B.V. All rights reserved.