Perspectives Newsletter Winter 2020
Vol. 42, no.4 / Posted on March 19, 2020

By Suresh Neethirajan, CSBE member

h5n1

Vaccines are the way to combat outbreaks, but it takes a little time to create a special vaccine for each outbreak. Currently, we are probably a year away from a vaccine for the Wuhan outbreak. Until that time, the indicated course of action is Quarantine, containment, and managing symptoms. But before any of that can happen, early identification is essential. Current methods require time, and a great expenditure of medical resources, many of which are not feasible in the field. Identification takes incubation time, many days sometimes. During that time, hundreds of people can be exposed. But new methods are on the horizon.

Nanotechnology To The Rescue

    Several new field identification tools are soon to be available. Nanotechnology is the process of using things that are smaller than 100 nanometers. A very promising method is the use of MoS² (Molybdenum bisulfate) treated cotton thread. Oral or Nasal Swab samples and/or a small blood sample, which can be easily and painlessly obtained in the field, such as an airport, or poultry farm, using something as simple as a diabetic lancing tool, is placed on the thread, and possibly in as little as 6 minutes, the sample will fluoresce if it is positive for exposure to the H5N1 viral proteins. The extent of exposure may be determined by the amount of fluorescence.

    Other similar methods are being developed using a Quantum Dot Matrix based on nanomaterials such as Zirconium. Like with the cotton thread method, the dots will fluoresce when exposed to antibody proteins for the H5N2 coronavirus. For an even more accurate identification, chiral plasmonic gold nanoparticles are used in a Quantum Dot Matrix. This results in a much lower limit for detection.

 

Tool 1: Rapid, ultra-sensitive, highly specific biosensors can detect coronavirus on the molecular level 

 Advances in nanotechnology have led to breakthroughs in how micro and nanofluidics can be used to develop immunosensing capabilities for biological substances. Ahmed and colleagues (2017) examined the use of an ultra-sensitive nanofluidic biosensor to detect various viruses, including major coronaviruses, in fowl blood samples. The coronaviruses probed included avian influenza A (H5N1) — also called bird flu — as well as fowl adenovirus and coronavirus.

Virus 1

  These ultrasensitive biosensors work by having very high specificity and sensitivity to the coronavirus — due to the fact that the biosensors interact with coronaviruses on the molecular and even nanoscale levels, which is why this technology is so incredibly powerful. For example, in a selectivity test for target virus H5N1 (avian influenza virus A, also called “avian flu” or “bird flu”), H1N1, H5N2, H7N8, and H7N9 were less selective to the sensor than the target virus, H5N1. Additionally, the nanosensor offered greater sensitivity than commercially available kits testing for H5N1.

  To demonstrate the efficacy of the nanofluidic immunosensor to detect coronavirus, the bionanolab tested their immunosensing nanofluidic device on chicken blood samples. The immunosensor was able to detect very low-level amounts of coronaviruses, with higher sensitivity and specificity than commercially available kits. Applied to the current epidemic, such advanced technology could help detect very minute levels of coronavirus and help ward off an epidemic — in humans as well as other animals who could stand to be devastated by this dangerous class of viruses. 

Tool 2: Improving optical detection of coronavirus via biosensors

  A main component of the bionano molecular diagnostic device is the use of nanoscale materials which enables optical detection of coronavirus. Optical sensors convert light rays into electronic signals, which serves as the primary detection method for coronavirus.

Virus 2

  The bionano lab team (2018) created a new class of nanoscale materials called chiral zirconium quantum dots (Zr QDs) for optical detection of coronavirus. This new nanomaterial significantly helped to improve the molecular specificity of the nanobiosensing platform to detect coronavirus. Quantum dots (QDs) are man-made crystals with a size in the nanoscale range (10–9 meters). QDs that contain zirconium (Zr) have promising characteristics such as strong fluorescence emission and optical stability; broad range of excitation length; better quantum yield; and a tunable emission peak which ranges from infrared to ultraviolet. These properties lend Zr QDs to biological applications such as coronavirus detection. However, these novel QDs could also help improve a variety of other biosensing and bioimaging applications.

  To demonstrate Zr QDs exceptional sensing qualities, the bionano team also used the model analyte of the avian coronavirus called infectious bronchitis virus (IBV). IBV can cause several physical symptoms in chickens; while it is a respiratory disease, it can also result in reduced egg production and fertility. The introduction of new IBV variants each year cuts into the poultry industry’s bottom line, so the researchers were eager to develop a highly sensitive and rapid detection method using this new technology. The newly synthesized Zr QDs showed greater sensitivity than conventional biodetection methods for IBV. Additionally, this optical-based bioassay may open new doors for research and offer further optical applications.

Tool 3: Immunosensing to rapidly detect avian coronavirus

  Following the success of the above mentioned studies conducted using a blood-based nanofluidics immunosensing platform, Weng and Neethirajan (2018) sought to develop a rapid, low-cost, sensitive biosensor for the detection of IBV. A cotton thread-based microfluidics platform was designed and developed as a diagnostic tool for low resource settings to reduce costs and take advantage of the good wicking properties and flexibilities of cotton thread.

  Common ways to diagnose coronaviruses — and, in fact, the gold standard — have been ELISA testing to look for coronavirus proteins and polymerase chain reaction (PCR) to probe for coronavirus biomarkers. However, these assays have some flaws — ELISA can only work when there is a large concentration of coronavirus molecules, which means that less severe cases go undetected; PCR can be expensive as it relies on costly reagents and staff skilled in PCR machine use and analysis. These challenges make on-site detection of coronoavirus a challenge, not only for human patients but also for animals (e.g., on a farm).

  Weng and Neethirajan used nanotechnology to develop a highly sensitive biosensor which could rapidly detect levels of IBV with a remarkable sensitivity and excellent specificity. Other benefits of this approach include validation with the ELISA method of IBV detection; ease of local manufacture; and small consumption of reagants and samples. The technology developed and tested offers potential applications for fast on-site detection of IBV and other coronaviruses.

On-Site Detection Tools Around the Corner

  The rapidly emerging novel form of coronavirus, 2019-nCoV, underscores the need for rapid detection of coronaviruses in humans and other animals. Advances in nanotechnology have made possible atomic and molecular level detection of coronaviruses using micro & nanofluidics applications. These 3 new tools developed by our team been validated against current methods of coronavirus detection and are faster, more sensitive, and more specific. These technologies have been demonstrated to work with avian populations and can have important applications on a farm to detect and screen for coronavirus to avoid the pathogen’s potentially devastating effects.

  This work also has implications for diagnosing humans with coronavirus. While more work is needed to bring this technology to human diagnostics, the technologies discussed above clearly indicate that the future of coronavirus diagnostics may be powered by immunosensors through state-of-the-art nanotechnology. With the development of nanotechnology, the threat from outbreaks of even serious diseases will be greatly reduced. The technology is just around the corner.

References

Weng, X. and Neethirajan, S., 2018. Immunosensor Based on Antibody-Functionalized MoS 2 for Rapid Detection of Avian Coronavirus on Cotton Thread. IEEE Sensors Journal18(11), pp.4358-4363.

Ahmed, S.R., Kang, S.W., Oh, S., Lee, J. and Neethirajan, S., 2018. Chiral zirconium quantum dots: A new class of nanocrystals for optical detection of coronavirus. Heliyon4(8), p.e00766.

Ahmed, S.R., Nagy, É. and Neethirajan, S., 2017. Self-assembled star-shaped chiroplasmonic gold nanoparticles for an ultrasensitive chiro-immunosensor for viruses. RSC advances7(65), pp.40849-40857.