New biochip diagnoses HIV/AIDS on the spot

A new sensor technology developed by researchers at the University of Illinois at Urbana-Champaign and collaborators at Daktari Diagnostics can diagnose HIV/AIDS using just a drop of blood. The device could provide less costly, easy-to-use, immediate disease diagnostics, especially useful in remote areas of the world and locations with limited resources.

Developed by the research group of Rashid Bashir, professor and head of the Department of Bioengineering at Illinois, the device uses a microfluidic biochip, a miniaturized chip designed to process fluids and sense the cells electronically. It works similar to a common blood sugar test, where a patient can put a drop of blood on a strip and insert the strip into a handheld reader to get a blood glucose result. In this case, the strip is a biochip inside of a cartridge, where white blood cells are captured in a microfluidic chamber coated with proteins.

The portable device provides information on the number of white blood cells and CD4+ T cells (immune cells that get destroyed when a patient is infected with the HIV virus) are in a drop of blood. Clinical diagnoses of AIDS are based on when CD4 cells get below 200-350 cells per microliter of whole blood.

Results of the research have been published in the cover article of the journal Science Translational Medicine. According to the paper's first co-authors, Nicholas Watkins and Umer Hassan, the approach can detect sub-populations of white blood cells, such as CD4+ and CD8+ T cells, and it can count white blood cells just as accurately as more complex time-consuming approaches using cell counting technologies that require larger volumes of blood. And, by using the CD4/CD8 ratio, doctors may obtain a more complete “picture” of HIV infection.

The group is working on miniaturizing the setup to make the technology handheld, as well as designing a cartridge that can be mass-produced. The biochip also could be used in many other situations where white blood cell counts are needed.

In addition to Watkins (now at Nabsys, Providence, RI) and Hassan, co-authors of the study include doctoral students Gregory Damhorst and HengKan Ni at Illinois, in addition to Awais Vaid (Champaign County Public Health District), William Rodriguez (Daktari Diagnostics, Inc.), and Rashid Bashir.

Rodriguez and Bashir are two of the co-founders of Daktari Diagnostics, a Boston-based company that is commercializing portable technologies for global health.

The article, "Microfluidic CD4+ and CD8+ T Lymphocyte Counters for Point-of-Care HIV Diagnostics Using Whole Blood" is available online.
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Contact: Rashid Bashir, Department of Bioengineering, 217/333-1867.

Writer: Susan McKenna, assistant director of communications, Department of Bioengineering, 217/333-1867.

Images: Umer Hassan