Zika Virus has become a growing international public health concern in the last decade. Despite the decrease in global outbreaks since 2016, the lack of vaccine development against the virus has kept Zika as a top research priority for the World Health Organization (WHO). New discoveries found that commercially available Zika IgM antibodies, currently used in applications for early detection of Zika, have high cross-reactivity rates to other potent flavivirus pathogens. In an effort to improve diagnosis, a novel platform using a graphene-based biosensor has been developed by Nanomedical Diagnostics Inc., in conjunction with the National Center for Emerging and Zoonotic Infectious Diseases (NCEZID).
This technology, in works with PEG as a blocking reagent, showed limited cross-reactivity when tested with Japanese Encephalitis Virus, which shares 56.5% sequence homology to ZIKV NS1.
"The high concentration of PEG used during blocking leads to both covalently linked PEG to the graphene surface and absorbed PEG to the rest of the chip surfaces. This provides both an anti-absorptive to the SiO2 as well as a stable block on the graphene against non-specific interactions at the surface."
Since PEG is hydrophilic, short PEG chains are often used to form a strong self-assembled monolayer to the graphene surface. This cluster produces an exclusion volume, preventing non-specific binding of other protein molecules.
PEG can also be produced in a heterobifunctional manner for optimal effects. For this experiment, an Amino-PEG5-Alcohol was used to quench any residual active NHS groups on the surface of the sensor chips, supporting a highly specific interaction for Zika detection.
Hopefully, as new methods and technology continue to expand, understanding of these techniques will open more opportunities for accurate viral detection.