You feel sick—you’ve had a runny nose, fever, sore throat, and non-stop cough for over a week. You go buy a box of facial tissues from the grocery store. You sneeze into the tissue and the tissue turns a bright blue. This means you weren’t just suffering from a common cold—but you actually have been infected by West Nile virus.
Picture a world where a diagnosis kit for almost any specific illness is readily available over-the-counter at your neighborhood grocery store. No need to schedule an expensive doctor’s appointment and endure unnecessary waiting periods. You pick up a box of biosensing tissues, finger-prick tests, or urine tests to find out what your health problem is as soon as you get home.
While this scenario may be more of a hypochondriac’s fantasy, biosensor development could revolutionize human healthcare practices around the world. Biosensor engineering is a quickly growing field of interest due to its practicality, with thousands of related research papers being published in the recent decade (Hasan et al., 2014). Despite this, there are few popularly manufactured commercial biosensors with the exception of lateral flow pregnancy tests and electrochemical glucose sensors. Developing more sustainable, convenient, and cost-effective health diagnostic tools is important as many diseases go undiagnosed each year. A recent report from the American Diabetes Association speculates that nearly 7.2 million Americans suffer from diabetes, but have not been diagnosed (Drive, Arlington, & Va 22202 1-800-Diabetes, n.d.). The healthcare industry is set up in such a way that the most common routine is for a person to wait until symptoms are very serious, perhaps even beyond the point where treatment is a viable option, before visiting a doctor. But what if any person had easy access to all the tools for disease diagnosis? Early detection could prevent life-or-death scenarios in addition to saving time and money.
First isolated in Uganda in 1937, West Nile Virus (WNV) is a neurological disease most commonly transmitted from birds to humans and other mammals via infected mosquitoes (“West Nile Virus Transmission,” 2018). Since its discovery, this virus has been identified throughout Africa, parts of Europe, the Middle East, Australia, and the Americas (“West Nile Virus,” n.d.). It is now one of the most prevalent mosquito-borne illnesses worldwide. In 2018, there were 2544 reports of human infection, 137 of which lead to death. According to the World Health Organization, current West Nile virus diagnostic methods include:
· IgG and IgM enzyme-linked immunosorbent assay (ELISA)
· Neutralization assay
· Reverse transcription polymerase chain reaction (RT-PCR) assay
· Isolation of virus from cell culture
While these methods are often standard laboratory techniques, they are specific tests that are costly, laborious, and yield time-delayed results. Specific diseases such as West Nile virus are often unsuspected when a person’s symptoms emerge. Although West Nile virus has no vaccine or cure, a timely diagnosis would allow a person to seek treatment options that will prevent the serious side effects of the disease. Biosensor research and development could help commercialize disease diagnosis so that a person could quickly pinpoint the cause of their symptoms.
For this year’s BIOMOD project, we worked on engineering a molecular beacon covalently installed in a host protein crystal to detect West Nile Virus. Because protein crystals can withstand a variety of pH levels and temperatures, a biosensor contained within a protein crystal could inspire greater versatility in biosensor design (Hartje & Snow, n.d.). The host crystals were created using a mutated periplasmic protein from Campylobacter jejuni (CJ). When crystallized, this protein forms hexagonal crystals, in which proteins dimerize to form each of the sides. As a result of the protein architecture small pores form on all sides of the crystal. The mutated version of the CJ protein used, CJ Greg, results in cysteine residues located in each of the pores. The molecular beacon was designed to covalently install in these pores, not only for protection--but also as a housing to concentrate beacon fluorescence.
Check out our Computational Lab Notebook and Experimental Lab Notebook to learn more about our design and methods!
Drive, A. D. A. 2451 C., Arlington, S. 900, & Va 22202 1-800-Diabetes. (n.d.). Statistics About Diabetes. Retrieved June 16, 2019, from American Diabetes Association website: http://www.diabetes.org/diabetes-basics/statistics/
Hartje, L. F., & Snow, C. D. (n.d.). Protein crystal based materials for nanoscale applications in medicine and biotechnology. Wiley Interdisciplinary Reviews: Nanomedicine and Nanobiotechnology, 0(0), e1547. https://doi.org/10.1002/wnan.1547
Hasan, A., Nurunnabi, M., Morshed, M., Paul, A., Polini, A., Kuila, T., … Jaffa, A. A. (2014). Recent Advances in Application of Biosensors in Tissue Engineering [Research article]. https://doi.org/10.1155/2014/307519
West Nile Virus. (n.d.). Retrieved June 10, 2019, from World Health Organization website: https://www.who.int/news-room/fact-sheets/detail/west-nile-virus
West Nile Virus Transmission. (2018, December 10). Retrieved June 7, 2019, from U.S. Centers for Disease Control website: https://www.cdc.gov/westnile/transmission/index.html