BDI ARTICLE FEATURES AS JALA COVER ARTICLE
Recently, the microfluidics group of Prof. Jens Ducrée completed 2 years of development on a system designed for rapid and accurate HIV diagnostics in resource-poor regions where the pandemic is concentrated. One of the solutions developed has been featured as the cover article of the Journal of Laboratory Automation (JALA) for the June issue. JALA is the academic journal published by the Society for Laboratory Automation and Screening (SLAS), an organisation that bridges the gap between academia, industry and government to advance new automation strategies for biomedical technologies ranging from Point-of-Care to capital instrumentation.
The BDI test described in the article is based on monitoring the number of CD4+ cells in the blood of an individual. These cells moderate the immune system but are also the primary host for the HIV virus, and are progressively destroyed as infection advances. Loss of CD4+ cells leads to gradual erosion of the immune system and eventual emergence of acquired immunodeficiency, or AIDS. Monitoring the concentration of CD4+ in a blood sample hence gives both a diagnostic of HIV infection, as well as an indication of the severity of infection. The test developed in the BDI is a centrifugal microfluidic platform, where small quantities of blood (extracted via finger-prick – much like a diabetes test) are mixed with tiny magnetic beads that attach only to the CD4+ cells in the blood sample. The mixed sample is then placed into a microfluidic channel that is housed within a disc shaped cartridge. When spun, the blood sample will travel through the microfluidic channels to the outer region of the disc, but the CD4+ cells are attracted to a small chamber by an on-disc magnet. Here, the cell concentration can be estimated by measuring the amount of material attracted to the capture chamber. Both the size of the disc, and the speeds required to spin it, are similar to those of a conventional DVD, thus potentially allowing the test to be performed on standard technology such as a DVD-ROM drive. The work presented in the article represents a convergence of technologies developed in the microfluidics group in the BDI, and is an open platform where simply changing the specificity of the magnetic beads can allow a number of other biomedical tests to be carried out using the same instrument and cartridge.
The list of authors exemplifies the diversity of research taking place in the BDI. The primary author, Macdara Glynn, is a cellular biologist; but other authors cover a range of disciplines such as Daniel Kirby (physics), David Kinahan (engineering), and Gregor Kijanka (biotechnology). Additionally, the list demonstrates the quality of students being trained in the BDI, as Danielle Chung (then an undergraduate student) generated much of the data that formed the basis of the paper during her final year project.
An advancement of the technology has also recently been published in the journal Lab on a Chip, one of the Royal Society of Chemistry (RSC) journals (DOI: 10.1039/c4lc00264d). The authors found that the technology behind the CD4+ cell isolation could be performed without the need for a centrifuge, and could operate largely instrument-free. These factors are critical for deployment of realistic and rapid HIV diagnostics in regions where electricity and expertise are minimal.