Revzin, a UC
Davis biomedical engineer professor, along
with UCLA electrical
engineer Prof. Aydogan Ozcan, have created a microfluidic device,
on a chip," specifically for HIV testing.
"lab on a chip" instructs antibodies to detect and
"capture" HIV-infected white
blood cells called T-cells, and the test then calculates the levels
and types of cytokines (inflammatory proteins) that the
cells are releasing. It is a holographic, lens-free imaging
mechanism that counts the number of cytokine molecules and captured
T-cells and is able to deliver results in seconds, which is six to 12
times faster than other related blood sample tests.
test is made of polymer film with an array of miniature spots that
contain antibodies that are specific to the CD4 and CD8 T-cells as
well as three different types of cytokines which are "printed in
the same array." The T-cells stop and stick on these miniature
spots when blood flows across them. Then, T-cell types are captured
on antibody spots "specific for the cytokines they might
produce," and antibodies activate the cells helping spots
adjacent to the cells catch cytokines they secreted. With T-cell
subsets now connected to their secreted cytokines, the antibody
spots' visible color intensity allows
researchers to see differences in cytokine production, which
makes T-cell count possible without mechanical scanning or lenses.
and monitoring HIV today requires many highly trained specialists and
expensive machines in
order to count two types of T-cells, calculate the ratio between them
and count cytokines as well. The process is called flow cytometry,
and AIDS activists and healthcare workers have been asking for easier
and less expensive ways to test for HIV.
response to these requests, this particular "lab on a chip"
test is currently being altered so it can be used for
multi-parametric blood analysis in both the developing world and
"resource-poor" areas. It is also affordable, and Revzin is
hoping it will be available for clinical use at some point.
the point of care field focuses on detection of single parameter
(e.g. CD4 counts), we believe that the simplicity of the test need
not compromise information content," said Revzin. "So, we
set out to develop a test that could be simple and inexpensive but
would provide several parameters based on a single injection of a
small blood volume."
and his team along with Ozcan published their
study on the HIV testing device in Analytical