Researchers at Brigham Young University are reporting the development of a microfluidic device that is able to sort individual virus particles based on size. In addition to potentially being used one day in the clinical setting as a diagnosis modality, this technology should provide researchers with high speed sorting of pathogens for laboratory work.
The chips work like coin sorters, only they are much, much smaller. Liquids flow until they hit a wall where big particles get stuck and small particles pass through a super-thin slot at the bottom. Each chip’s slot is set a little smaller than the size of the particle to be detected. After the particles get trapped against the wall, they form a line visible with a special camera.
Capturing single particles has important applications besides simply knowing if a particular virus or protein is present.
“One of the things I hope to see is for these chips to become a tool for virus purification,” said David Belnap, an assistant professor of chemistry and co-author on the paper.
He explained that a tool like the BYU chip would advance the pace of his research, allowing him and other researchers to consistently obtain pure samples essential for close inspection of viruses.
A huge barrier to making chips that can detect viruses is $100 million – that’s the cost of machinery precise enough to make chips with nano-sized parts necessary for medical and biological applications.
The BYU group developed an innovative solution. First they used a simpler machine to form two dimensions in micrometers — 1,000 times larger than a nanometer. They formed the third dimension by placing a 50 nanometer-thin layer of metal onto the chip, then topping that with glass deposited by gasses. Finally they used an acid to wash away the thin metal, leaving the narrow gap in the glass as a virus trap.
So far, the chips have one slot size. Hawkins [Aaron Hawkins, professor of electrical and computer engineering at BYU] says his team will make chips soon with progressively smaller slots, allowing a single channel to screen for particles of multiple sizes. Someone “reading” such a chip would easily be able to determine which proteins or viruses are present based on which walls have particles stacked against them.
After perfecting the chips’ capabilities, the next step, Hawkins says, is to engineer an easy-to-use way for a lab technician to introduce the test sample into the chip.
Brigham Young press release: ‘Lab on a chip’ that detects viruses developed by BYU researchers…
Abstract in Lab on a Chip: Selective trapping and concentration of nanoparticles and viruses in dual-height nanofluidic channels