Researchers at the Technical University of Munich (TUM) have developed a new method to treat viral infections by making traps. The team folded DNA into nano-capsules with specialized binding points inside them, which could grab hold of viruses and render them inert.
For the last few years the team has been experimenting with programming DNA to fold into “blocks” and plates which then assemble into shapes like origami. For the new work the researchers decided to see if they could use this technology to make hollow bodies that were about the size of a virus, which could then clamp over the bugs and prevent them from infecting cells.
To do so, the team started with a shape called an icosahedron, which is made up of 20 triangular surfaces. Using DNA origami they created a half-shell of 180 subunits, and lined the center with molecules that bind to viruses. The outer surfaces are then irradiated with UV light and treated with polyethylene glycol and oligolysine, to keep the traps from degrading in body fluids.
The team tested the traps in lab cell cultures, containing mouse serum, human cells and viruses. The structures remained stable in the serum for 24 hours, and successfully captured two different types of viruses – hepatitis B and adeno-associated viruses (AAVs). In both cases, the traps prevented the viruses from infecting human cells.
"Even a simple half-shell of the right size shows a measurable reduction in virus activity," says Hendrik Dietz, corresponding author of the study. "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.”
The concept of a virus trap sounds a little familiar, but takes a different approach. Last year another team of German scientists designed bacteriophages that mimic structures in lung cells that the flu virus binds to, which reduces the number of viruses that go on to infect the real cells.
The researchers say that the next step is to test these traps in mice, and they expect that they should be well-tolerated by the human body. And the underlying tech of building nanostructures out of DNA origami could eventually have other applications as well.
"In addition to the proposed application as a virus trap, our programmable system also creates other opportunities," says Dietz. "It would also be conceivable to use it as a multivalent antigen carrier for vaccinations, as a DNA or RNA carrier for gene therapy or as a transport vehicle for drugs."
The research was published in the journal Nature Materials.
Source: Technical University of Munich
