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Proceedings Paper

Fluorescent intensity-based differential counting of FITC-doped silica nanoparticles: applications of CD4+ T-cell detection in microchip-type flowcytometers
Author(s): Hoyoung Yun; Hyunwoo Bang; Won Gu Lee; Hyunchang Lim; Junha Park; Joonmo Lee; Asif Riaz; Keunchang Cho; Chanil Chung; Dong-Chul Han; Jun Keun Chang
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Paper Abstract

Although CD4+ T-cells are an important target of HIV detection, there have been still major problems in making a diagnosis and monitoring in the third world and the region with few medical facilities. Then, it is necessary to use portable diagnosis devices at low cost when you put an enumeration of CD4+ T-cells. In general, the counting of CD4 below 200cells/uL makes it necessary to initiate antiretroviral treatment in adults (over 13 years old). However, lymphocyte subsets (including CD4 counts) of infants and young children are higher than those of adults. This fact shows the percentage of CD4+ T-cells of blood subsets, i.e., CD4/CD45%, CD4/CD8% or CD4/CD3% means a more reliable indicator of HIV infection than absolute counts in children. To know the percentage of CD4+ T-cell by using two fluorescent dyes of different emission wavelength, at least, one laser and two PMT detectors are in general needed. Then, it is so hard to develop a portable device like a 'toaster size' because this makes such a device more complex including many peripheral modules. In this study, we developed a novel technique to control the intensity of fluorescent dye-doped silica nanoparticles. I synthesized FITC-doped silica nanoparticles conjugated CD4 antibody 10 times brighter than FITC-conjugated CD45 antibody. With the difference of intensity of two fluorescent dyes, we measured two parameters by using only a single detector and laser. Most experiments were achieved with uFACS (microfabricated fluorescence-activated cell sorter) on an inverted microscope (IX71, Olympus). In conclusion, this method enables us to discriminate the difference between CD4 and CD45 in an intensity domain simultaneously. Furthermore, this technique would make it possible develop much cheaper and smaller devices which can count the number of CD4 T-cells.

Paper Details

Date Published: 14 December 2006
PDF: 8 pages
Proc. SPIE 6416, Biomedical Applications of Micro- and Nanoengineering III, 641605 (14 December 2006); doi: 10.1117/12.695975
Show Author Affiliations
Hoyoung Yun, Seoul National Univ. (South Korea)
Hyunwoo Bang, Seoul National Univ. (South Korea)
Won Gu Lee, Seoul National Univ. (South Korea)
Hyunchang Lim, Seoul National Univ. (South Korea)
Junha Park, Digital Bio Technology, Inc. (South Korea)
Joonmo Lee, Seoul National Univ. (South Korea)
Asif Riaz, Univ. of California, Berkeley (United States)
Keunchang Cho, Digital Bio Technology, Inc. (South Korea)
Chanil Chung, Digital Bio Technology, Inc. (South Korea)
Dong-Chul Han, Seoul National Univ. (South Korea)
Jun Keun Chang, Digital Bio Technology, Inc. (South Korea)

Published in SPIE Proceedings Vol. 6416:
Biomedical Applications of Micro- and Nanoengineering III
Dan V. Nicolau, Editor(s)

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