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.