DETECTION OF HUMAN T-LYMPHOCYTES WITH A PIEZOELECTRIC IMMUNOSENSOR

A reusable piezoelectric immunosensor was developed for the detection of purified human T-lymphocytes and of T-lymphocytes in whole human blood. Three different methods for immobilization of anti CD 3 gp M(r) 19 000-29 000 antibody on the gold electrode of the immunosensor were tested. Coating the electrode with polyethyleneimine gave the best results in terms of stability, sensitivity and reproducibility. Similar results were observed on coating the electrode with gamma-aminopropyltriethoxysilane. The last method, coating the electrode with protein A, gave inferior results. Applying an anti CD 3 gp M(r) 19000-29000 antibody layer via polyethyleneimine immobilization on a 10-MHz AT-cut crystal resulted in 5 x 10(3)-4.5 x 10(5) cells on the surface in a linear frequency change and a long-term stability of 10 weeks when the modified crystal was stored desiccated at room temperature.