Portable test to monitor HIV Reliably assessing the status of the immune system in HIV infected patients is essential to effective treatment of the virus. The HIVBIOCHIP project aims to develop a portable, inexpensive imaging system to count the number of CD4 + T-cells in HIV infected patients, helping improve the effectiveness of treatment, as Professor Nikos Chronis explains The treatment of HIV has advanced significantly over recent years, with highly active antiretroviral therapies (HAART) now available that promise to improve quality of life for infected patients. These treatments should be regularly adjusted to reflect the patient’s condition and help them maintain a healthy immune system, as Professor Nikos Chronis explains. “A patient should be tested every few weeks or so, to make sure that they take the correct dose and the right cocktail of drugs,” he outlines. This can be difficult in remote areas of the developing world, where HIV infection rates are often high, an issue that Professor Chronis and his colleagues in the HIVBIOCHIP project are working to address. “The idea in the project is to develop a portable, inexpensive device to perform HIV monitoring tests out in the field, where often there is no available infrastructure,” he says. CD4+ T-cells This device is designed to count the number of CD4 + T cells in a blood sample, which is an important indicator of the health of the immune system. Researchers are developing both a biochip and an imaging system, which can image and count cells in 1 microliter of whole blood within minutes. “First you have to prick your finger with a needle (like diabetic patients do) and then touch the chip, which draws the blood, and the blood cells are then immobilized on the surface of the biochip,” explains Professor Chronis. While previously it was necessary to prepare and treat the blood sample before the CD4 + T-cells could be imaged, Professor Chronis says that these further steps aren’t required with the project’s biochip. “The imaging scanner takes images using white light rather than fluorescence, and at the end it reports the concentration of the CD4 + T-cells to either the doctor or the patient, most likely the doctor or someone with medical training,” he outlines. The device itself is portable, self-contained and battery-powered, so well-suited for use in remote locations in the developing world. In some areas of the developing world
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Microfluidics combined with advanced micro-optics technology can enable monitoring of HIV-infected patients in resource-limited settings at the point-of-care. infection rates can be as high as 20 percent, yet with effective monitoring of the immune system and the right treatment, patients can control the condition. “By regularly monitoring the progression of the disease and taking the right drugs, HIV can be controlled, it basically becomes like a chronic disease,” says Professor Chronis. The project’s work holds clear promise in these terms, and Professor Chronis says there are plans to bring their research to the commercial marketplace. “The project is not only about developing a prototype and testing it with healthy volunteers, but also about building a commercialisation plan,” he says. A positive application of the system in the developed world would help to attract investment, so researchers are looking to use the scanner to count other types of cells, aside from CD4 + T-cells. One example would be looking at how cancer treatment affects the immune system by counting the number of white blood cells, and there are many other possibilities. “This device is a platform, it’s not limited to CD4 + T-cells, it could be used for any type of cell,” says Professor Chronis. There are two simple modifications in adapting the platform to count other types of blood cells. “If you want to trap a different type of cell, you have to functionalise the biochip surface with a different type of antibody that will
recognise the specific type of cell that you’re looking for,” explains Professor Chronis. The second modification is in adapting the imaging recognition algorithm that identifies the cells. “If you’re looking for another type of cell, then you might have to train the algorithm to identify the type of cell that you’re looking for,” says Professor Chronis. A point-of-care Biochip for HIV monitoring in the developing world (HIVBIOCHIP) Professor Nikos Chronis National Center for Scientific Research ‘Demokritos” End of Patriarchou Grigoriou E and 27 Neapoleos Street 15341 Agia Paraskevi Greece T: +30 2106 503 000 E: chronis@umich.edu W: http://erc.europa.eu/ Professor Nikos Chronis received his B.E. and Ph.D. degrees from Aristotle University (Greece) and University of California at Berkeley in 1998 and 2004 respectively, both in mechanical engineering. In 2004, he worked as a postdoctoral researcher in Cori Bargmann’s lab at Rockefeller University. In 2006, he joined the faculty of Mechanical Engineering at the University of Michigan. His research interests include implantable MEMS sensors, point-of-care microfluidics and in-vivo imaging of neuronal circuits.
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