Researchers at the Technical University of Munich have developed a method to create tiny virus traps that can bind viral particles and render them harmless within the body. The technique relies on DNA origami to create self-assembling hollow nanocapsules, which are lined with molecules that will bind viruses and prevent them from leaving. With a viral pandemic currently running riot, such technologies should be very welcome for the future.
Effective anti-viral drugs are elusive for many viral infections, COVID-19 being no exception. These researchers have developed a new type of anti-viral technology that does not rely on small-molecule viral inhibitors, but instead employs a nano-sized viral trap that can engulf and immobilize viral particles within the body.
“Bacteria have a metabolism. We can attack them in different ways,” said Ulrike Protzer, a researcher involved in the study. “Viruses, on the other hand, do not have their own metabolism, which is why antiviral drugs are almost always targeted against a specific enzyme in a single virus. Such a development takes time. If the idea of simply mechanically eliminating viruses can be realized, this would be widely applicable and thus an important breakthrough, especially for newly emerging viruses.”
The technology uses DNA to form the building blocks of the trap structure, but as DNA is quite fragile within the body, the researchers used UV light and polyethylene glycol to stabilize the material before use. After this treatment, the nanostructures were stable for 24 hours in serum from mice.
The structure is composed of 3D triangular plates that can slot together. “In this way, we can now program the shape and size of the desired objects using the exact shape of the triangular plates,” said Hendrik Dietz, another researcher involved in the study. “We can now produce objects with up to 180 subunits and achieve yields of up to 95 percent. The route there was, however, quite rocky, with many iterations.”
So far, the researchers tested the viral traps in the lab, and showed that they can immobilize hepatitis B viral particles and adeno-associated viruses. “Even a simple half-shell of the right size shows a measurable reduction in virus activity,” said Dietz. “If we put five binding sites for the virus on the inside, for example suitable antibodies, we can already block the virus by 80 percent, if we incorporate more, we achieve complete blocking.”
Here’s a short video showing a cryo-EM 3D reconstruction of an open nano-shell:
Study in Nature Materials: Programmable icosahedral shell system for virus trapping