Development of quartz-crystal-microbalance-based immunosensor array for clinical immunophenotyping of acute leukemias.

An integrated piezoelectric immunosensor array has been developed to immunophenotype acute leukemias in clinic. Each quartz crystal microbalance (QCM) was fabricated with plasma-polymerized film of n-butylamine, nanogold particles, and protein A (PA) to be used to immobilize antibodies in orientation. Leukemic lineage-associated monoclonal antibodies were separately immobilized onto the nanogold-PA-modified surface of the crystals, which were constructed by a 2 x 2 type of probes forming a QCM-based immunosensor array. The main detection conditions were investigated, including the immobilization amount of antibodies, pH, immunoreaction time, sample dilution ratio, etc. The immunophenotyping feasibility of the new technique was investigated through simultaneously analyzing Jurkat cells by the immunosensor array method, immunohistochemistry, and flow cytometry. It was found that the developed technique could readily identify leukemia samples in 5 min and might monitor dynamically the immunoreaction processes. Moreover, comparison studies were carried out for CD antigens expressed on the nucleated cells isolated from 96 acute leukemic patients and 24 normal subjects using the QCM-based immunosensor method and the fluoroimmunoassay. Results obtained by immunophenotyping patients' samples with the immunosensor-based method achieved the rate of 88.93% in 768 groups of numerical data, where no significant statistical difference was observed between the two methods when checked by chi2 analysis (chi2 = 3.4, p > 0.05). This new immunosensor array showed the merits of high sensitivity, high specificity, good reproducibility, easy operation, and low cost. The results of specimen evaluation indicated that it might be clinically suitable for quantifying human differentiated leukocytes and immunophenotyping of acute leukemias.