Paper-based immunosensors: the future of HIV diagnoses?
Researchers from McGill University (Montreal, QC, Canada) have developed a new paper-based electrochemical immunosensing platform, which may provide an inexpensive and portable solution to point-of-care diagnoses of sexually transmitted infections. In particular, it could be utilized for the diagnosis of HIV/AIDS and hepatitis C virus (HCV) co-infection, which affects a third of patients with HIV.
At present, rapid point-of-care tests are available in developed countries. However, these are expensive and do not have the capability to accurately quantify stage-specific disease marker concentrations.
The sensitivity of the new device, discussed recently in Biomicrofluidics, was tested with mouse serum samples. It was demonstrated to detect HIV and HCV antibodies at 300pg / ml and 750pg / ml, respectively, indicating a higher sensitivity than existing platforms.
The platform comprises a paper device with eight electrochemical sensors, intended for single, disposable use, and a hand-held electrochemical reader, termed a potentiostat. Xinyu Liu, McGill University, commented: “It enables eight [simultaneous tests], four for HIV antibodies, and four for HCV antibodies.” This makes the test both more affordable and broader than existing HIV and HCV point-of-care tests.
The researchers also explored the potential of a cross-reaction between HIV and HCV antibody tests: they observed no significant interference between the two. Lui added: “These results demonstrate that our diagnostic platform shows great potential for diagnosing HIV/HCV co-infections in real patient samples.”
The main advantages of this new testing platform over existing devices lie in its ability to run eight tests for HIV and HCV in parallel in under 20 min, along with high specificity, accuracy and sensitivity. The platform has the capability to transmit test results to a remote site, such as a laboratory or health center, offering an additional benefit to the device.
While currently tested as a immunosensor for HIV and HCV, the authors suggest that the portable electrochemical detection model could be utilized to detect other disease biomarkers such as proteins, metabolites and nucleic acids.
Going forward, Liu suggests that the next steps will involve improving the device for practical use: “We’ll explore the stability of the paper device during long-term storage, and then begin real patient sample testing in Canada and Kenya. Our long-term goal is to further extend the functionality of this diagnostic platform by targeting other molecular disease markers.”
Sources: Zhao C, Liu X. A portable paper-based microfluidic platform for multiplexed electrochemical detection of human immunodeficiency virus and hepatitis C virus antibodies in serum. Biomicrofluidics 10, 024119. doi:10.1063/1.4945311 (2016); AIP press release.
