As highly-contagious Covid-19 subvariants proliferate, two U.S. researchers are using photonic biosensors on a chip to fight back with a wider scope of immunity testing.
“What we are doing,” said Ben Miller, professor at the University of Rochester, “is showing how to quickly adapt a test assay to a new variant.”
“Rather than just test for one protein from one virus, we can look at several different variants, and find out, in a minute or so, if antibodies are present that bind to other variants.” That information, in turn, can help guide medical responses.
The chips, which may be on the road to markets by 2024, will measure about 25mm (1in) square and a3mm (one-eighth of an inch) thick. The system, using silicon nitride sensors, won’t be just for Covid; it can also test for immunity to flu and many other diseases.
The main industry partner, Ortho-Clinical Diagnostics, based in Rochester, NY, is considering the future product for its customer base, said Nate Cady, a team member and professor at SUNY Poly in Albany, 200 miles east of Rochester. Originally a spinoff from Kodak, Ortho-Clinical was recently acquired by Quidel Corp..
Another Rochester industry partner, Syntec Optics, will carry out injection molding to create the disposable part of the assay.
The AIM foundry in Albany, which has manufactured thousands of chips for Miller’s previous diagnostic-based research, will also be designing packaging for the new immunity-based project.
If a new Covid subvariant appears in a community, even a remote one without expensive hospital equipment, staff without high-level training could quickly adapt the chip to test for the newest variant, demonstrating the strengths of photonic approaches.
AIM, or The American Institute for Manufacturing Photonics, based in Albany, N.Y., won a grant of $5 million for the research with American Rescue Plan funds. That Plan was enacted in 2021 to deliver $1.9 trillion to various agencies to combat the pandemic, which has caused at least 6 million deaths – maybe far more – globally.
Looking at blood samples, the AIM chip will make accurate tests to see if a patient still has protection from Covid antibodies. The tests will answer questions such as, “Did the vaccination work? Do I have the right antibodies? How long will that immunity last? Do I need to get another booster?”
“The photonic technology is working in the lab now,” said Cady. But it’s not ready to go into production yet, he said, and that’s the heart of the new grant. In 2020, the project team led by Miller devised a chip to perform Covid antibody sensing in a small and inexpensive format. While the assay consumable was small and inexpensive, it use a $150,000 lab laser system for reading and analysis.
“The new smaller device is an outgrowth of that project,” Miller said, “to detect the various antibodies in a blood sample that bind to 2019 SARS CoV-2.”
‘Cheaper and more compact reader’
Now, their goal is to make the reader compact and much cheaper, simple enough to work in a clinic without extensive training. “We’re asking, how small can we miniaturize it?” said Cady. “We are flipping the antigen tests upside down. We are putting a piece of a virus onto a chip with a photonic sensor. They we look for antibodies in the blood to grab onto the piece of the virus on our chip.”
The new project is called Rapid Assistance for Coronavirus Economic Response, or RACER. Some of the grant funds will provide fabrication runs at the AIM chip photonics foundry, and will also provide talent to execute the complex research.
Academic partners include Rochester Institute of Technology, or RIT; SUNY Polytechnic Institute; the University of California Santa Barbara; and the U.S. Naval Research Lab.
In short, said Miller, the new research is no longer just about finding one protein from one virus infection but about looking at several different ones and in turn adapting the assays. The information about immunity protection will be central to guide people in decisions about getting vaccinated again.
“This will tell us, if there’s a new variant and I get my blood tested, I’ll know if the antibodies I have from vaccination or prior infection bind to it,” Miller said. “I may need a new vaccine, or not.”
The most common virus tests, called PCR, for Polymerase Chain Reaction, “are terrific for diagnosing Covid,” Miller said, “but there aren’t good PCR tests for immunity. We will help people understand their immunity.”
A second theme of Miller’s research with AIM will focus on providing Covid information to residents living in a resource-limited environment, perhaps in a remote or rural area without a nearby hospital or other more complex systems.
When a diagnostic laboratory runs a diagnostic assay to look at a blood sample, the sample usually needs to go through a complex optical system, at a heavily resourced facility, like a hospital or clinical laboratory setting.
“That’s where RIT is joining in, to miniaturize the reader optical system,” Miller said. Then, the signal can be read at a point-of-care location, perhaps a doctor’s office, with minimal resources.
The work may take two years, Miller said. Beyond that, he hopes that a large company will want to move the technology forward, “to pick it up and run with it. We have to get the technology far enough that it’s worthwhile to the company to make that happen.”
Beyond assays for immunity, Miller indicated the project will also be testing the technology for the detection of human proteins associated with Covid-19 infection. “This is an important way to extend the usefulness of the technology in Covid response,” Miller said, “but also will demonstrate that the disposable chip-on-a-card concept can be used for a broad range of human diagnostics.”
Interest in the product will be world-wide, Miller said, but he said “it’s still pretty early” to say whether a U.S. company or one overseas will take the lead.
“It won’t be something you will see walking in to Walgreen’s next year,” he said, “but when it’s ready we expect a company will move it forward.”
Original Source: Optics