Researchers have created a new diagnostic tool that can detect SARS-CoV-2 and Zika virus with the same level of accuracy as high-precision PCR tests, and in a much shorter time frame. For the past four years, many people have been familiar with the nasal swab testing for COVID-19 using at-home rapid antigen tests or the more precise PCR tests offered in clinics. The new tool, developed by UC Santa Cruz Distinguished Professor Holger Schmidt and his team, has the ability to accurately test for SARS-CoV-2 and Zika virus.PCR tests that are highly accurate can be completed in just a few hours.
A recent article in the journal Proceedings of the National Academy of Sciences details a new system created by Schmidt and the project team. This new system integrates optofluidics and nanopore technology to develop a lab-on-a-chip diagnostic system. The success of this system with animal models has led the team to believe that it could be a significant advancement for rapid diagnostics in the future.
“This has the potential to become the next major diagnostic system,” noted Aaron Hawkins, a professor of Electrical and Computer Engineering at Brigham Young University and one of the senior authors of the article.”You become ill, you visit the hospital or doctor, and their tests depend on this technology. There’s a possibility that this could be implemented directly in a hospital or clinic, so you wouldn’t have to wait for your results.”
This study is the outcome of a long-term collaboration between Schmidt, Hawkins, and Professor Jean Patterson at the Texas Biomedical Research Institute.
Quicker and more precise tests
Although PCR testing is currently considered the most accurate method for virology testing, it has several drawbacks. PCR tests are extremely complex and require chemical reactions that must be perfPerformed by skilled operators, often at a centralized laboratory, PCR testing can sometimes take days to produce results. This lengthy process is necessary to amplify viral DNA or RNA, essentially making multiple copies of the genetic material, which can also introduce and amplify errors.
Additionally, PCR tests are limited to detecting nucleic acids, the building blocks of DNA and RNA. However, in the case of certain diseases, it is valuable to be able to detect other biomarkers such as proteins.
The new diagnostic tool addresses both of these issues by requiring minimal sample preparation and completely amplifying the material.The new diagnostic system is revolutionary in that it is both cation-free and label-free, meaning it does not use light to identify biomarkers. This significantly simplifies and speeds up the diagnosis process. According to Patterson, the potential of this system is enormous, as it does not require amplification to produce accurate results. The system combines Schmidt’s expertise in optofluidics, which involves controlling small amounts of fluids with light beams, with a nanopore for counting individual nucleic acids to read genetic material.The tool was created to detect the presence of Zika and COVID-19 viruses, which have been particularly important in the field of medicine in recent years and are a top priority for the National Institutes of Health, who funded this research.
“We developed a basic lab-on-a-chip system that can conduct testing on a small scale using microfluidics, silicon chips, and nanopore detection technologies,” explained Mohammad Julker Neyen Sampad, a graduate student working with Schmidt and the first author of the paper. “Our goal was to create a simple, easy-to-use tool that requires minimal resources – and I believe we have achieved that.”
In order to perform the test, a sample of biofluid is combined in a container with mThe researchers in this study at Texas Biomedical Research Institute used biofluids such as saliva and blood from baboons and marmosets. The magnetic microbeads are designed with a specific RNA sequence matching the disease being tested for, such as SARS-CoV-2 for a COVID-19 detection test. If the virus is present in the sample, its RNA will bind to the beads. The researcher can then pull the magnetic beads to the bottom of the container and wash away everything else after a short waiting period.The beads are placed in a silicon microfluidics chip created by Hawkins’ team, where they move through a long, narrow channel covered by an ultra-thin membrane, which Hawkins describes as an “engineering miracle.” The beads are trapped in a light beam that pushes them against a wall in the channel, which includes a nanopore, a tiny 20-nanometer opening — to put it in perspective, a human hair is about 80,000-100,000 nanometers wide.
The scientists heat the chip, causing the RNA particles to detach from the beads and enter the nanopore, which identifies the presence of virus RNA.
Positive findings
Their experiments demonstrated that the test accurately identified the virus in every sample that the PCR test could detect, even at very low levels of the virus. There were cases where the PCR test missed a virus that Schmidt’s system was able to detect, indicating that their system may be more precise than PCR.
In general, the microfluidics system is smaller and less intricate than a PCR machine. If this idea is developed into a product, its small size could easily fit in a researcher’s lab, allowing for much quicker virology testing and increasing the efficiency of the process.
Testing accessibility and reducing result turnaround time from days to hours has been a focus.
“By creating an instrument using this system, a researcher could conduct testing in a biosafety level-4 lab where the sample never leaves the room. A small sample liquid can be inserted, and the test can be completed in an hour,” Schmidt explained. “This could potentially accelerate the testing process.”
The test involved six different biofluids, such as saliva, blood, and throat swabs, all of which may contain varying levels of viruses. This allows researchers to study how diseases spread through the bodies of different organisms more effectively.
While the test is currently in its initial phase, the team has made significant progress in terms of improving testing accessibility and speeding up the time to results.It was created for the purpose of detecting SARS-CoV-2 and Zika viruses, but researchers are able to make modifications to identify any virus for which they have a genetic sample. They are also working on making the system simpler and smaller, as well as allowing it to test for multiple diseases at the same time, a feature known as disease multiplexing.
Schmidt also plans to use this idea to create diagnostic tools for cancer biomarkers and other health conditions that leave traces of DNA/RNA or protein in the body. It will likely take a few years before this concept is available for commercial use.
Journal Reference:
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Mohammad Julker Neyen Sampad, S. M. Saiduzzaman, Zach J. Walker, Tanner N. Wells, Jesse X. Wayment, Ephraim M. Ong, Stephanie D. Mdaki, Manasi A. Tamhankar, Thomas D. Yuzvinsky, Jean L. Patterson, Aaron R. Hawkins, Holger Schmidt. Label-free and amplification-free viral RNA quantification from primate biofluids using a trapping-assisted optofluidic nanopore platform. Proceedings of the National Academy of Sciences, 2024; 121 (16) DOI: 10The article can be found at the following link: .1073/pnas.2400203121. Thank you for your interest in this content.