Fluorescent Labeling, Sensing and Differentiation of Leukocytes from Undiluted Whole Blood Samples
In this paper, we demonstrated leukocyte labeling, sensing and differentiation from undiluted human whole blood samples with microfabricated devices. A challenging issue in leukocyte sensing from blood samples is the required high dilution level, which is used mainly to prevent interference from the overwhelmingly outnumbered erythrocytes. Dilution is undesirable for micro hemacytometers. It not only increases sample volume and processing time, but also requires mixing and buffer storage for on- chip implementation. Unlike commercial bulk instruments and previous efforts by other groups, we completely eliminated the requirement for dilution by staining leukocytes specifically with fluorescent dye acridine orange (AO) in undiluted human whole blood and then sensing them in microfluidic devices. Green fluorescent signal centered at 525 nm was used for leukocyte count and red fluorescent signal centered at 650 nm was used for leukocyte differentiation. Throughput of one hundred leukocytes per second was achieved, which means operation time for one sample only requires several seconds.
Additional Information© 2007 IEEE. The authors would like to thank for all the members at Caltech Micromachining Group for their value assistance. Also the authors would like to thank for Mr. Zhaoyu Zhang from California Institute of Technology for his discussion and assistance. This work was supported by the National Space Biomedical Research Institute through NASA NCC 9-58.
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