(103d) Electrical Detection of Zika Virus on Paper Microchip with Silver-Graphene-Nano-Composite Electrode

Mohamed Shehata Draz, Harini Lakshminarayanan, Manasa Venkataramani, Kamyar Mehrabi, Maryam Moazeni, Hadi Shafiee

Division of Engineering in Medicine, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA 02115, USA

Abstract:

Zika virus is a member of the flavivirdae family. It is primarily transmitted by Aedes mosquito to human. Recently, there are increasing reports confirming that Zika can pass from mother to fetus during pregnancy causing severe microcephaly and other birth defects. There are currently no effective vaccines for Zika infection and the laboratory-based methods for Zika detection are challenging. There are no specific clinical features of Zika infection and the developed symptoms can be mistaken for those of dengue fever and Chikungunya infection. The current Zika infection detection methods mainly rely on identifying either viral RNA or IgM antibodies using RNA nucleic acid Testing (RNA NAT) or MAC-ELISA assay, respectively. However, RNA is detectable in whole blood for only 14 days after the onset of symptoms, and thus a negative RNA NAT result does not exclude infection. On the other hand, the results of Zika MAC-ELISA are unreliable due to the cross-reactivity with other Flaviviruses. The development of rapid, low-cost Zika infection diagnostics can shift the paradigm in the management of infection. Here, we developed a paper-based microchip with printed microelectrodes for Zika virus detection using electrical sensing of viral lysate. The microchip was fabricated using cellulose paper substrate (0.18 mm in thickness), a thin plastic sheet (0.1 mm in thickness), and a double-sided adhesive (DSA). Finger-like integrated electrodes were screen-printed on the paper-plastic substrate using silver-graphene nanocomposite followed by 120 min drying step at 50 ⁰C. The target viruses were captured on magnetic beads conjugated with anti-Zika antibodies. The captured viruses were then washed with a low-electrically conductive solution to remove the electrically conductive background solution. The captured viruses were then lysed using 1% Triton X-100 to release the charged molecules into the non-ionic background solution. This viral lysate step changes the electrical conductivity of the solution that can be detected as a biomarker signal using impedance spectroscopy on-chip. The results showed that the impedance magnitude of the bulk samples were directly proportional to the concentration of the virus in spiked samples. Our results showed that the chip was able to detect Zika viruses in samples with viral loads as low as 10² copies/μL. To evaluate the specificity of the microchip, we challenged the system with Zika virus and different non-targeted viruses, such as Dengue-1, Dengue-2, HSV, HIV, and CMV. The results confirmed the ability of the microchip to specifically detect Zika virus from other non-targeted viruses including closely related flaviviruses such as Dengue-1 and Dengue-2. The developed assay is simple, rapid, cost-effective and sensitive and it can potentially be used for point-of-care diagnosis of Zika virus.