DEVELOPMENT OF A PIEZOELECTRIC IMMUNOSENSOR FOR THE DETECTION OF HUMAN ERYTHROCYTES

A reusable piezoelectric immunosensor was developed for the detection of purified human erythrocytes and erythrocytes in whole human blood. Three different methods for immobilization of anti-glycophorin A antibody to the gold electrode were tested. Coating the electrode with polyethylenimine gave the best results in terms of stability, sensitivity and reproducibility. The other two methods, coating the electrode with gamma-aminopropyltriethoxysilane and protein A, gave inferior results. Applying an anti-glycophorin A antibody layer via polyethylenimine immobilization on a 10-MHz AT-cut crystal resulted in a linear frequency change for 1 x 10(3) - 5 x 10(4) cells ml-1.